diff --git a/lava_flan.lua b/lava_flan.lua
index 5bf23fa..55de98f 100644
--- a/lava_flan.lua
+++ b/lava_flan.lua
@@ -41,6 +41,7 @@ mobs:register_mob("mobs_monster:lava_flan", {
 	immune_to = {
 		{"mobs:pick_lava", -2}, -- lava pick heals 2 health
 	},
+	fly_in = {"default:lava_source", "default:lava_flowing"},
 	animation = {
 		speed_normal = 15,
 		speed_run = 15,
@@ -62,21 +63,7 @@ mobs:register_mob("mobs_monster:lava_flan", {
 
 			pos.y = pos.y + 1
 
-			minetest.add_particlespawner({
-				amount = 40,
-				time = 0.25,
-				minpos = pos,
-				maxpos = pos,
-				minvel = {x = -2, y = 0, z = -2},
-				maxvel = {x = 2, y = 2, z = 2},
-				minacc = {x = 0, y = 0, z = 0},
-				maxacc = {x = 0, y = 10, z = 0},
-				minexptime = 0.1,
-				maxexptime = 1,
-				minsize = 3.0,
-				maxsize = 5.0,
-				texture = "tnt_smoke.png",
-			})
+			mobs:effect(pos, 40, "tnt_smoke.png", 3, 5, 2, 0.5, nil, false)
 
 			minetest.sound_play("fire_extinguish_flame",
 				{pos = pos, max_hear_distance = 12, gain = 1.5}, true)
@@ -84,28 +71,16 @@ mobs:register_mob("mobs_monster:lava_flan", {
 			self.object:remove()
 
 			if math.random(4) == 1 then
-				minetest.add_entity(pos, "mobs_monster:obsidian_flan")
+				mobs:add_mob(pos, {
+					name = "mobs_monster:obsidian_flan",
+				})
 			end
 		else
 			if minetest.get_node(pos).name == "air" then
 				minetest.set_node(pos, {name = "fire:basic_flame"})
 			end
 
-			minetest.add_particlespawner({
-				amount = 20,
-				time = 0.25,
-				minpos = pos,
-				maxpos = pos,
-				minvel = {x = -2, y = -2, z = -2},
-				maxvel = {x = 2, y = 2, z = 2},
-				minacc = {x = 0, y = -10, z = 0},
-				maxacc = {x = 0, y = -10, z = 0},
-				minexptime = 0.1,
-				maxexptime = 1,
-				minsize = 1.0,
-				maxsize = 2.0,
-				texture = "fire_basic_flame.png",
-			})
+			mobs:effect(pos, 40, "fire_basic_flame.png", 2, 3, 2, 5, 10, nil)
 
 			self.object:remove()
 		end
@@ -257,9 +232,10 @@ mobs:register_mob("mobs_monster:obsidian_flan", {
 	floats = 0,
 	drops = {
 		{name = "default:obsidian_shard", chance = 1, min = 1, max = 5},
+		{name = "default:obsidian", chance = 3, min = 0, max = 2},
 	},
 	water_damage = 0,
-	lava_damage = 0,
+	lava_damage = 8,
 	light_damage = 0,
 	animation = {
 		speed_normal = 15,
@@ -321,7 +297,9 @@ mobs:register_arrow("mobs_monster:obsidian_arrow", {
 			texture = def.tiles[1]
 		end
 
-		if def.groups and def.groups.level == 2 then
+		-- do not break obsidian or diamond blocks or unbreakable nodes
+		if (def.groups and def.groups.level and def.groups.level > 1)
+		or def.groups.unbreakable then
 			return
 		end
 
diff --git a/sand_monster.lua b/sand_monster.lua
index 27881cc..413bd52 100644
--- a/sand_monster.lua
+++ b/sand_monster.lua
@@ -96,9 +96,9 @@ mobs:register_mob("mobs_monster:sand_monster", {
 ]]
 	on_die = function(self, pos)
 		pos.y = pos.y + 0.5
-		effect(pos, 30, "mobs_sand_particles.png", 0.1, 2, 3, 5)
+		mobs:effect(pos, 30, "mobs_sand_particles.png", .1, 2, 3, 5)
 		pos.y = pos.y + 0.25
-		effect(pos, 30, "mobs_sand_particles.png", 0.1, 2, 3, 5)
+		mobs:effect(pos, 30, "mobs_sand_particles.png", .1, 2, 3, 5)
 	end,
 --[[
 	on_rightclick = function(self, clicker)