NPC_ENTITY.on_step = function(self, dtime)
    self.timer = self.timer + 0.01
    self.turn_timer = self.turn_timer + 0.01
    self.jump_timer = self.jump_timer + 0.01
    self.door_timer = self.door_timer + 0.01
    self.attacking_timer = self.attacking_timer + 0.01
    local name = minetest.env:get_node(pos).name
    if minetest.get_item_groups(name, "water") ~= 0 then
        self.object:set_hp(0)
    end