diff --git a/mods/ENTITIES/mcl_mobs/api.lua b/mods/ENTITIES/mcl_mobs/api.lua
index f8881d7416..f1df87e8b7 100644
--- a/mods/ENTITIES/mcl_mobs/api.lua
+++ b/mods/ENTITIES/mcl_mobs/api.lua
@@ -283,6 +283,33 @@ local get_velocity = function(self)
 	return 0
 end
 
+local function update_roll(self)
+	local is_Fleckenstein = self.nametag == "Fleckenstein"
+	local was_Fleckenstein = false
+
+	local rot = self.object:get_rotation()
+	rot.z = is_Fleckenstein and pi or 0
+	self.object:set_rotation(rot)
+
+	local cbox = table.copy(self.collisionbox)
+	local acbox = self.object:get_properties().collisionbox
+
+	if math.abs(cbox[2] - acbox[2]) > 0.1 then
+		was_Fleckenstein = true
+	end
+
+	if is_Fleckenstein ~= was_Fleckenstein then
+		local pos = self.object:get_pos()
+		pos.y = pos.y + (acbox[2] + acbox[5])
+		self.object:set_pos(pos)
+	end
+
+	if is_Fleckenstein then
+		cbox[2], cbox[5] = -cbox[5], -cbox[2]
+	end
+
+	self.object:set_properties({collisionbox = cbox})
+end
 
 -- set and return valid yaw
 local set_yaw = function(self, yaw, delay, dtime)
@@ -298,6 +325,7 @@ local set_yaw = function(self, yaw, delay, dtime)
 			yaw = yaw + (math.random() * 2 - 1) * 5 * dtime
 		end
 		self.object:set_yaw(yaw)
+		update_roll(self)
 		return yaw
 	end
 
@@ -645,9 +673,9 @@ local update_tag = function(self)
 		nametag = tag,
 	})
 
+	update_roll(self)
 end
 
-
 -- drop items
 local item_drop = function(self, cooked, looting_level)
 
@@ -3487,6 +3515,7 @@ local mob_step = function(self, dtime)
 			yaw = yaw + (math.random() * 2 - 1) * 5 * dtime
 		end
 		self.object:set_yaw(yaw)
+		update_roll(self)
 	end
 
 	-- end rotation
diff --git a/mods/ENTITIES/mobs_mc/sheep.lua b/mods/ENTITIES/mobs_mc/sheep.lua
index 681c68e1b4..84650b4ddd 100644
--- a/mods/ENTITIES/mobs_mc/sheep.lua
+++ b/mods/ENTITIES/mobs_mc/sheep.lua
@@ -25,6 +25,19 @@ local colors = {
 	unicolor_black = { mobs_mc.items.wool_black, "#000000D0" },
 }
 
+local rainbow_colors = {
+	"unicolor_light_red",
+	"unicolor_red",
+	"unicolor_orange",
+	"unicolor_yellow",
+	"unicolor_green",
+	"unicolor_dark_green",
+	"unicolor_light_blue",
+	"unicolor_blue",
+	"unicolor_violet",
+	"unicolor_red_violet"
+}
+
 if minetest.get_modpath("mcl_wool") ~= nil then
 	colors["unicolor_light_blue"] = { mobs_mc.items.wool_light_blue, "#5050FFD0" }
 end
@@ -112,7 +125,7 @@ mobs:register_mob("mobs_mc:sheep", {
 	end,
 
 	-- Set random color on spawn
-	do_custom = function(self)
+	do_custom = function(self, dtime)
 		if not self.initial_color_set then
 			local r = math.random(0,100000)
 			local textures
@@ -149,8 +162,35 @@ mobs:register_mob("mobs_mc:sheep", {
 			}
 			self.initial_color_set = true
 		end
+
+		local is_kay27 = self.nametag == "kay27"
+
+		if self.color_change_timer then
+			local old_color = self.color
+			if is_kay27 then
+				self.color_change_timer = self.color_change_timer - dtime
+				if self.color_change_timer < 0 then
+					self.color_change_timer = 0.5
+					self.color_index = (self.color_index + 1) % #rainbow_colors
+					self.color = rainbow_colors[self.color_index + 1]
+				end
+			else
+				self.color_change_timer = nil
+				self.color_index = nil
+				self.color = self.initial_color
+			end
+
+			if old_color ~= self.color then
+				self.base_texture = sheep_texture(self.color)
+				self.object:set_properties({textures = self.base_texture})
+			end
+		elseif is_kay27 then
+			self.initial_color = self.color
+			self.color_change_timer = 0
+			self.color_index = -1
+		end
 	end,
-	
+
 	on_rightclick = function(self, clicker)
 		local item = clicker:get_wielded_item()