Extra error checking.

demon.lua

@@ -14,6 +14,10 @@ minetest.register_node("fun_caves:freezing_vapor", {
 })
 
 local function snow_effect(pos, radius)
+	if not (pos and radius and type(radius) == 'number') then
+		return
+	end
+
 	minetest.add_particlespawner({
 		amount = 30,
 		time = 1,
@@ -86,6 +90,10 @@ mobs:register_mob("fun_caves:ice_demon", {
 	animation_speed = 30,
 	fly_in = 'fun_caves:freezing_vapor',
 	do_custom = function(self)
+		if not self then
+			return
+		end
+
 		-- This has to happen fast.
 		if self.attack then
 			self.fly = true
@@ -163,6 +171,10 @@ local snow_demon = {
 	},
 	animation_speed = 30,
 	do_custom = function(self)
+		if not self then
+			return
+		end
+
 		if not self.attack then
 			self.fly = false
 		end
@@ -185,9 +197,17 @@ local snow_demon = {
 fun_caves.register_status({
 	name = 'slow_cold',
 	start = function(player)
+		if not player then
+			return
+		end
+
 		player:set_physics_override({speed=0.3})
 	end,
 	terminate = function(player)
+		if not player then
+			return
+		end
+
 		player:set_physics_override({speed=1})
 	end,
 })