apply spawn effect

half-earth/scripts/WorldGrid.cs

@@ -53,6 +53,7 @@ public class WorldGrid : Node2D
 
         var tile = _tileGrid[idx];
         tile.type = tileType;
+        tile = tileType.ApplySpawneffect(tile);
         _tileGrid[x, y] = tile;
     }
     #endregion

half-earth/scripts/tile/TileType.cs

@@ -17,4 +17,6 @@ public class TileType : Resource
     public float HeatGeneration { get; private set; }
 
     public override string ToString() => Name;
+
+    public virtual Tile ApplySpawneffect(Tile tile) => tile;
 }

half-earth/scripts/tile/Wild.cs

@@ -4,4 +4,10 @@ public class Wild : TileType, IDamageable
 {
     [Export]
     public float Threshold { get; private set; }
+
+    public override Tile ApplySpawneffect(Tile tile)
+    {
+        tile.currentHealth = 0;
+        return tile;
+    }
 }