diff --git a/core/assets/baseparts/752942460573057196.msch b/core/assets/baseparts/752942460573057196.msch
index 57b5e83b0a..6f81df2b4e 100644
Binary files a/core/assets/baseparts/752942460573057196.msch and b/core/assets/baseparts/752942460573057196.msch differ
diff --git a/core/src/mindustry/async/PhysicsProcess.java b/core/src/mindustry/async/PhysicsProcess.java
index 5e8b1be923..0f49176c57 100644
--- a/core/src/mindustry/async/PhysicsProcess.java
+++ b/core/src/mindustry/async/PhysicsProcess.java
@@ -43,6 +43,7 @@ public class PhysicsProcess implements AsyncProcess{
         //find entities without bodies and assign them
         for(Physicsc entity : group){
             boolean grounded = entity.isGrounded();
+            int bits = grounded ? flying.maskBits : ground.maskBits;
 
             if(entity.physref() == null){
                 //add bodies to entities that have none
@@ -66,12 +67,9 @@ public class PhysicsProcess implements AsyncProcess{
             //save last position
             PhysicRef ref = entity.physref();
 
-            if(ref.wasGround != grounded){
-                if(ref.body.getFixtureList().isEmpty()) continue;
-
+            if(ref.body.getFixtureList().any() && ref.body.getFixtureList().first().getFilterData().categoryBits != bits){
                 //set correct filter
                 ref.body.getFixtureList().first().setFilterData(grounded ? ground : flying);
-                ref.wasGround = grounded;
             }
 
             ref.velocity.set(entity.deltaX(), entity.deltaY());
@@ -143,10 +141,9 @@ public class PhysicsProcess implements AsyncProcess{
     }
 
     public static class PhysicRef{
-        Physicsc entity;
-        Body body;
-        boolean wasGround = true;
-        Vec2 lastPosition = new Vec2(), delta = new Vec2(), velocity = new Vec2(), lastVelocity = new Vec2(), position = new Vec2();
+        public Physicsc entity;
+        public Body body;
+        public Vec2 lastPosition = new Vec2(), delta = new Vec2(), velocity = new Vec2(), lastVelocity = new Vec2(), position = new Vec2();
 
         public PhysicRef(Physicsc entity, Body body){
             this.entity = entity;
diff --git a/core/src/mindustry/core/NetServer.java b/core/src/mindustry/core/NetServer.java
index f15c225f48..6174798e96 100644
--- a/core/src/mindustry/core/NetServer.java
+++ b/core/src/mindustry/core/NetServer.java
@@ -485,7 +485,7 @@ public class NetServer implements ApplicationListener{
         data.stream = new ByteArrayInputStream(stream.toByteArray());
         player.con.sendStream(data);
 
-        Log.debug("Packed @ invalid world data.", stream.size());
+        Log.debug("Packed @ bytes of world data.", stream.size());
     }
 
     public void addPacketHandler(String type, Cons2<Player, String> handler){
diff --git a/core/src/mindustry/entities/Units.java b/core/src/mindustry/entities/Units.java
index c93ecaffce..6460e9ce8d 100644
--- a/core/src/mindustry/entities/Units.java
+++ b/core/src/mindustry/entities/Units.java
@@ -99,7 +99,7 @@ public class Units{
 
         nearby(x, y, width, height, unit -> {
             if(boolResult) return;
-            if(unit.isGrounded() == ground){
+            if((unit.isGrounded() && !unit.type().hovering) == ground){
                 unit.hitbox(hitrect);
 
                 if(hitrect.overlaps(x, y, width, height)){
diff --git a/core/src/mindustry/entities/comp/LegsComp.java b/core/src/mindustry/entities/comp/LegsComp.java
index 9cc5d876e2..68c0de5f00 100644
--- a/core/src/mindustry/entities/comp/LegsComp.java
+++ b/core/src/mindustry/entities/comp/LegsComp.java
@@ -30,6 +30,30 @@ abstract class LegsComp implements Posc, Rotc, Hitboxc, Flyingc, Unitc{
         collisions.moveCheck(this, cx, cy, !type.allowLegStep ? EntityCollisions::solid : EntityCollisions::legsSolid);
     }
 
+    @Override
+    public void add(){
+        resetLegs();
+    }
+
+    public void resetLegs(){
+        float rot = baseRotation;
+        int count = type.legCount;
+        float legLength = type.legLength;
+
+        this.legs = new Leg[count];
+
+        float spacing = 360f / count;
+
+        for(int i = 0; i < legs.length; i++){
+            Leg l = new Leg();
+
+            l.joint.trns(i * spacing + rot, legLength/2f + type.legBaseOffset).add(x, y);
+            l.base.trns(i * spacing + rot, legLength + type.legBaseOffset).add(x, y);
+
+            legs[i] = l;
+        }
+    }
+
     @Override
     public void update(){
         if(Mathf.dst(deltaX(), deltaY()) > 0.001f){
@@ -37,23 +61,11 @@ abstract class LegsComp implements Posc, Rotc, Hitboxc, Flyingc, Unitc{
         }
 
         float rot = baseRotation;
-        int count = type.legCount;
         float legLength = type.legLength;
 
         //set up initial leg positions
         if(legs.length != type.legCount){
-            this.legs = new Leg[count];
-
-            float spacing = 360f / count;
-
-            for(int i = 0; i < legs.length; i++){
-                Leg l = new Leg();
-
-                l.joint.trns(i * spacing + rot, legLength/2f + type.legBaseOffset).add(x, y);
-                l.base.trns(i * spacing + rot, legLength + type.legBaseOffset).add(x, y);
-
-                legs[i] = l;
-            }
+            resetLegs();
         }
 
         float moveSpeed = type.legSpeed;
diff --git a/core/src/mindustry/mod/Scripts.java b/core/src/mindustry/mod/Scripts.java
index d2009187f7..14a9e4326f 100644
--- a/core/src/mindustry/mod/Scripts.java
+++ b/core/src/mindustry/mod/Scripts.java
@@ -22,7 +22,7 @@ public class Scripts implements Disposable{
     private final Seq<String> blacklist = Seq.with(".net.", "java.net", "files", "reflect", "javax", "rhino", "file", "channels", "jdk",
         "runtime", "util.os", "rmi", "security", "org.", "sun.", "beans", "sql", "http", "exec", "compiler", "process", "system",
         ".awt", "socket", "classloader", "oracle", "invoke", "java.util.function", "java.util.stream", "org.");
-    private final Seq<String> whitelist = Seq.with("mindustry.net", "netserver", "netclient", "com.sun.proxy.$proxy", "mindustry.gen.", "mindustry.logic.");
+    private final Seq<String> whitelist = Seq.with("mindustry.net", "netserver", "netclient", "com.sun.proxy.$proxy", "mindustry.gen.", "mindustry.logic.", "mindustry.async.");
     private final Context context;
     private final Scriptable scope;
     private boolean errored;
diff --git a/core/src/mindustry/type/UnitType.java b/core/src/mindustry/type/UnitType.java
index 3a83bb9cb7..973fd13c6f 100644
--- a/core/src/mindustry/type/UnitType.java
+++ b/core/src/mindustry/type/UnitType.java
@@ -112,6 +112,17 @@ public class UnitType extends UnlockableContent{
         return unit;
     }
 
+    public Unit spawn(Team team, float x, float y){
+        Unit out = create(team);
+        out.set(x, y);
+        out.add();
+        return out;
+    }
+
+    public Unit spawn(float x, float y){
+        return spawn(state.rules.defaultTeam, x, y);
+    }
+
     public boolean hasWeapons(){
         return weapons.size > 0;
     }
diff --git a/core/src/mindustry/world/Block.java b/core/src/mindustry/world/Block.java
index 255e269ecb..3e3006383f 100644
--- a/core/src/mindustry/world/Block.java
+++ b/core/src/mindustry/world/Block.java
@@ -196,7 +196,7 @@ public class Block extends UnlockableContent{
     /** Whether this block has instant transfer.*/
     public boolean instantTransfer = false;
 
-    protected Prov<Building> entityType = null; //initialized later
+    public Prov<Building> buildType = null; //initialized later
     public ObjectMap<Class<?>, Cons2> configurations = new ObjectMap<>();
 
     protected TextureRegion[] generatedIcons;
@@ -217,7 +217,7 @@ public class Block extends UnlockableContent{
 
     public Block(String name){
         super(name);
-        initEntity();
+        initBuilding();
     }
 
     public void drawBase(Tile tile){
@@ -499,8 +499,8 @@ public class Block extends UnlockableContent{
         return destructible || update;
     }
 
-    public final Building newEntity(){
-        return entityType.get();
+    public final Building newBuilding(){
+        return buildType.get();
     }
 
     public Rect bounds(int x, int y, Rect rect){
@@ -576,7 +576,7 @@ public class Block extends UnlockableContent{
         Arrays.sort(requirements, Structs.comparingInt(i -> i.item.id));
     }
 
-    protected void initEntity(){
+    protected void initBuilding(){
         //attempt to find the first declared class and use it as the entity type
         try{
             Class<?> current = getClass();
@@ -585,13 +585,13 @@ public class Block extends UnlockableContent{
                 current = current.getSuperclass();
             }
 
-            while(entityType == null && Block.class.isAssignableFrom(current)){
+            while(buildType == null && Block.class.isAssignableFrom(current)){
                 //first class that is subclass of Building
                 Class<?> type = Structs.find(current.getDeclaredClasses(), t -> Building.class.isAssignableFrom(t) && !t.isInterface());
                 if(type != null){
                     //these are inner classes, so they have an implicit parameter generated
                     Constructor<? extends Building> cons = (Constructor<? extends Building>)type.getDeclaredConstructor(type.getDeclaringClass());
-                    entityType = () -> {
+                    buildType = () -> {
                         try{
                             return cons.newInstance(this);
                         }catch(Exception e){
@@ -607,9 +607,9 @@ public class Block extends UnlockableContent{
         }catch(Throwable ignored){
         }
 
-        if(entityType == null){
+        if(buildType == null){
             //assign default value
-            entityType = Building::create;
+            buildType = Building::create;
         }
     }
 
diff --git a/core/src/mindustry/world/Tile.java b/core/src/mindustry/world/Tile.java
index 8d6b0841ae..ba303750e1 100644
--- a/core/src/mindustry/world/Tile.java
+++ b/core/src/mindustry/world/Tile.java
@@ -45,7 +45,7 @@ public class Tile implements Position, QuadTreeObject, Displayable{
         this.block = wall;
 
         //update entity and create it if needed
-        changeEntity(Team.derelict, wall::newEntity, 0);
+        changeEntity(Team.derelict, wall::newBuilding, 0);
         changed();
     }
 
@@ -174,7 +174,7 @@ public class Tile implements Position, QuadTreeObject, Displayable{
     }
 
     public void setBlock(@NonNull Block type, Team team, int rotation){
-        setBlock(type, team, rotation, type::newEntity);
+        setBlock(type, team, rotation, type::newBuilding);
     }
 
     public void setBlock(@NonNull Block type, Team team, int rotation, Prov<Building> entityprov){
diff --git a/core/src/mindustry/world/blocks/environment/Floor.java b/core/src/mindustry/world/blocks/environment/Floor.java
index 410980bcff..6640613779 100644
--- a/core/src/mindustry/world/blocks/environment/Floor.java
+++ b/core/src/mindustry/world/blocks/environment/Floor.java
@@ -103,9 +103,8 @@ public class Floor extends Block{
         super.init();
 
         if(wall == Blocks.air){
-            wall = content.block(name + "Rocks");
-            if(wall == null) wall = content.block(name + "rocks");
-            if(wall == null) wall = content.block(name.replace("darksand", "dune") + "rocks");
+            wall = content.block(name + "-wall");
+            if(wall == null) wall = content.block(name.replace("darksand", "dune") + "-wall");
         }
 
         //keep default value if not found...
diff --git a/core/src/mindustry/world/blocks/payloads/BlockPayload.java b/core/src/mindustry/world/blocks/payloads/BlockPayload.java
index fe91be7035..3fc87dbe6b 100644
--- a/core/src/mindustry/world/blocks/payloads/BlockPayload.java
+++ b/core/src/mindustry/world/blocks/payloads/BlockPayload.java
@@ -14,7 +14,7 @@ public class BlockPayload implements Payload{
     public Building entity;
 
     public BlockPayload(Block block, Team team){
-        this.entity = block.newEntity().create(block, team);
+        this.entity = block.newBuilding().create(block, team);
     }
 
     public BlockPayload(Building entity){
diff --git a/tests/src/test/java/ApplicationTests.java b/tests/src/test/java/ApplicationTests.java
index f13f430a4d..d689dbd5df 100644
--- a/tests/src/test/java/ApplicationTests.java
+++ b/tests/src/test/java/ApplicationTests.java
@@ -377,7 +377,7 @@ public class ApplicationTests{
         world.tile(length + 1, 0).setBlock(new Block("___"){{
             hasItems = true;
             destructible = true;
-            entityType = () -> new Building(){
+            buildType = () -> new Building(){
                 @Override
                 public void handleItem(Building source, Item item){
                     itemsa[0] ++;
diff --git a/tests/src/test/java/power/ItemLiquidGeneratorTests.java b/tests/src/test/java/power/ItemLiquidGeneratorTests.java
index 64959780d1..08f636c566 100644
--- a/tests/src/test/java/power/ItemLiquidGeneratorTests.java
+++ b/tests/src/test/java/power/ItemLiquidGeneratorTests.java
@@ -39,7 +39,7 @@ public class ItemLiquidGeneratorTests extends PowerTestFixture{
                 powerProduction = 0.1f;
                 itemDuration = fakeItemDuration;
                 maxLiquidGenerate = maximumLiquidUsage;
-                entityType = ItemLiquidGeneratorBuild::new;
+                buildType = ItemLiquidGeneratorBuild::new;
             }
 
             @Override
diff --git a/tests/src/test/java/power/PowerTestFixture.java b/tests/src/test/java/power/PowerTestFixture.java
index 1c888070bf..994130a596 100644
--- a/tests/src/test/java/power/PowerTestFixture.java
+++ b/tests/src/test/java/power/PowerTestFixture.java
@@ -43,21 +43,21 @@ public class PowerTestFixture{
 
     protected static PowerGenerator createFakeProducerBlock(float producedPower){
         return new PowerGenerator("fakegen"){{
-            entityType = () -> new GeneratorBuild();
+            buildType = () -> new GeneratorBuild();
             powerProduction = producedPower;
         }};
     }
 
     protected static Battery createFakeBattery(float capacity){
         return new Battery("fakebattery"){{
-            entityType = () -> new BatteryBuild();
+            buildType = () -> new BatteryBuild();
             consumes.powerBuffered(capacity);
         }};
     }
 
     protected static Block createFakeDirectConsumer(float powerPerTick){
         return new PowerBlock("fakedirectconsumer"){{
-            entityType = Building::create;
+            buildType = Building::create;
             consumes.power(powerPerTick);
         }};
     }
@@ -86,7 +86,7 @@ public class PowerTestFixture{
             Reflect.set(Tile.class, tile, "floor", Blocks.sand);
 
             // Simulate the "changed" method. Calling it through reflections would require half the game to be initialized.
-            tile.build = block.newEntity().init(tile, Team.sharded, false, 0);
+            tile.build = block.newBuilding().init(tile, Team.sharded, false, 0);
             if(block.hasPower){
                 tile.build.power.graph = new PowerGraph(){
                     //assume there's always something consuming power