diff --git a/api.lua b/api.lua
index 7de2c06..4124ff3 100644
--- a/api.lua
+++ b/api.lua
@@ -16,6 +16,7 @@ function mobs:register_mob(name, def)
 		light_damage = def.light_damage,
 		water_damage = def.water_damage,
 		lava_damage = def.lava_damage,
+		disable_fall_damage = def.disable_fall_damage,
 		drops = def.drops,
 		armor = def.armor,
 		drawtype = def.drawtype,
@@ -125,7 +126,7 @@ function mobs:register_mob(name, def)
 				self.object:setacceleration({x=0, y=-10, z=0})
 			end
 			
-			if self.object:getvelocity().y == 0 then
+			if self.disable_fall_damage and self.object:getvelocity().y == 0 then
 				if not self.old_y then
 					self.old_y = self.object:getpos().y
 				else
diff --git a/init.lua b/init.lua
index 21f2362..d1bc16e 100644
--- a/init.lua
+++ b/init.lua
@@ -139,6 +139,7 @@ mobs:register_mob("mobs:tree_monster", {
 	water_damage = 1,
 	lava_damage = 5,
 	light_damage = 2,
+	disable_fall_damage = true,
 	attack_type = "dogfight",
 	animation = {
 		speed_normal = 15,