diff --git a/decogen.lua b/decogen.lua
index a56c748..022e6b6 100644
--- a/decogen.lua
+++ b/decogen.lua
@@ -25,12 +25,8 @@ local plant_noise = {offset = 0.0, scale = 1.0, spread = {x = 200, y = 200, z =
 
 
 -- Air needs to be placed prior to decorations.
-fun_caves.decogen = function(minp, maxp, data, p2data, area, node, heightmap, biome_ids, underzone, dis_map)
+fun_caves.decogen = function(minp, maxp, data, p2data, area, node, heightmap, biomemap, biome_ids, underzone, dis_map)
 	csize = vector.add(vector.subtract(maxp, minp), 1)
-	local biomemap
-	if fun_caves.use_bi_hi then
-		biomemap = minetest.get_mapgen_object("biomemap")
-	end
 
 	local map_max = {x = csize.x, y = csize.y + 2, z = csize.z}
 	local map_min = {x = minp.x, y = minp.y - 1, z = minp.z}
diff --git a/mapgen.lua b/mapgen.lua
index f1e47a9..106a9f6 100644
--- a/mapgen.lua
+++ b/mapgen.lua
@@ -364,7 +364,7 @@ local function generate(p_minp, p_maxp, seed)
 	math.randomseed(minetest.get_perlin(seed_noise):get2d({x=minp.x, y=minp.z}))
 
 	local write = false
-	local write_p2 = false
+	local write_p2, write_p4 = false, false
 	local underzone
 	for _, uz in pairs(fun_caves.underzones) do
 		local avg = (minp.y + maxp.y) / 2
@@ -374,6 +374,7 @@ local function generate(p_minp, p_maxp, seed)
 	end
 
 	local aster = false
+	local true_casket
 	if minp.y > 17200 then
 		-- nop
 	elseif minp.y > 11000 then
@@ -388,21 +389,29 @@ local function generate(p_minp, p_maxp, seed)
 		fun_caves.fortress(minp, maxp, data, area, node)
 		write = true
 	else
-		local write1, write2, write3, h2
+		local write1, write2, write3, write4, h2
 		write1, h2 = fun_caves.cavegen(minp, maxp, data, area, node, heightmap, underzone)
 		if h2 then
 			heightmap = h2
 		end
 
-		write2, write_p2 = fun_caves.decogen(minp, maxp, data, p2data, area, node, heightmap, biome_ids, underzone)
+		local biomemap
+		if fun_caves.use_bi_hi then
+			biomemap = minetest.get_mapgen_object("biomemap")
+		end
+
+		write2, write_p2 = fun_caves.decogen(minp, maxp, data, p2data, area, node, heightmap, biomemap, biome_ids, underzone)
 		write3 = fun_caves.treegen(minp, maxp, data, p2data, area, node)
-		write = write1 or write2 or write3
+		if not write3 then
+			write4, write_p4, true_casket = fun_caves.pyramid(minp, maxp, data, p2data, area, biomemap, biome_ids, node, heightmap)
+		end
+		write = write1 or write2 or write3 or write4
 	end
 
 
 	if write then
 		vm:set_data(data)
-		if write_p2 then
+		if write_p2 or write_p4 then
 			vm:set_param2_data(p2data)
 		end
 
@@ -418,6 +427,13 @@ local function generate(p_minp, p_maxp, seed)
 		end
 		vm:update_liquids()
 		vm:write_to_map()
+
+		if true_casket then
+			vm:update_map()
+			local meta = minetest.get_meta(true_casket)
+			local id = meta:set_string('true', 'true')
+			--print('* True casket at '..minetest.pos_to_string(true_casket))
+		end
 	end
 
 	-- Deal with memory issues. This, of course, is supposed to be automatic.
@@ -435,6 +451,7 @@ dofile(fun_caves.path .. "/cavegen.lua")
 dofile(fun_caves.path .. "/cloudgen.lua")
 dofile(fun_caves.path .. "/decogen.lua")
 dofile(fun_caves.path .. "/fortress.lua")
+dofile(fun_caves.path .. "/pyramid.lua")
 dofile(fun_caves.path .. "/treegen.lua")
 dofile(fun_caves.path .. "/skyseagen.lua")
 
diff --git a/mobs.lua b/mobs.lua
index 8c03ce5..21d3092 100644
--- a/mobs.lua
+++ b/mobs.lua
@@ -635,6 +635,7 @@ if minetest.registered_entities["mobs_monster:sand_monster"] then
 	mobs.spawning_mobs["fun_caves:sand_monster"] = true
 
 	mobs:register_spawn("fun_caves:sand_monster", {"default:sand"}, 20, 0, 4000, 3, -50)
+	mobs:register_spawn("fun_caves:sand_monster", {"fun_caves:pyramid_1"}, default.LIGHT_MAX - 1, 0, 200, 5, 31000)
 
 	mobs:register_egg("fun_caves:sand_monster", "Deep Sand Monster", "default_sand.png", 1)
 end
diff --git a/pyramid.lua b/pyramid.lua
new file mode 100644
index 0000000..26b1e2b
--- /dev/null
+++ b/pyramid.lua
@@ -0,0 +1,143 @@
+local max_depth = 31000
+
+-- pyramid stone
+newnode = fun_caves.clone_node("default:sandstone")
+newnode.description = "Pyramid Stone"
+newnode.groups.pyramid = 1
+newnode.drop = 'default:sandstone'
+minetest.register_node("fun_caves:pyramid_1", newnode)
+
+local newnode = fun_caves.clone_node("default:chest")
+newnode.description = "Treasure Casket"
+local chest_formspec =
+	"size[8,9]" ..
+	default.gui_bg ..
+	default.gui_bg_img ..
+	default.gui_slots ..
+	"list[current_name;main;0,0.3;8,4;]" ..
+	"list[current_player;main;0,4.85;8,1;]" ..
+	"list[current_player;main;0,6.08;8,3;8]" ..
+	"listring[current_name;main]" ..
+	"listring[current_player;main]" ..
+	default.get_hotbar_bg(0,4.85)
+
+local filler = {'default:apple 10', 'default:coal_lump 10', 'default:wood 10'}
+
+local gems = {'fun_caves:moonstone', 'fun_caves:coral_gem', 'fun_caves:garnet', 'fun_caves:aquamarine', 'fun_caves:zoisite'}
+
+newnode.on_rightclick = function(pos, node, clicker, itemstack, pointed_thing)
+	local meta = minetest.get_meta(pos)
+	local true_casket = meta:get_string('true')
+	if true_casket ~= 'true' then
+		clicker:set_hp(clicker:get_hp() - 2)
+		--print('* ouch!')
+		return
+	end
+
+	local ready = meta:get_string('formspec')
+	if ready == '' then
+		meta:set_string("formspec", chest_formspec)
+		local inv = meta:get_inventory()
+		inv:set_size("main", 8*4)
+		for i = 1, math.random(4) do
+			inv:add_item('main', filler[math.random(#filler)])
+		end
+		inv:add_item('main', gems[math.random(#gems)])
+	end
+end
+minetest.register_node("fun_caves:casket", newnode)
+
+
+local pyramid_biomes = {}
+for _, i in pairs({"rainforest", "desert", "desertstone_grassland", }) do
+	pyramid_biomes[i] = true
+end
+
+local pyramid_noise_1 = {offset = 0, scale = 1, seed = -6012, spread = {x = 20, y = 10, z = 20}, octaves = 6, persist = 1, lacunarity = 2}
+
+
+fun_caves.pyramid = function(minp, maxp, data, p2data, area, biomemap, biome_ids, node, heightmap)
+	if math.random(10) ~= 1 then
+		return
+	end
+
+	if biomemap then
+		local biome = biome_ids[biomemap[3240]]
+		if not pyramid_biomes[biome] then
+			return
+		end
+		--print('* Creating pyramid in '..biome)
+	elseif math.random(5) ~= 1 then
+		return
+	end
+
+
+	local min_y = 80
+	local index = 0
+	for z = minp.z, maxp.z do
+		local dz = z - minp.z
+		for x = minp.x, maxp.x do
+			local dx = x - minp.x
+			index = index + 1
+			if dz > 8 and dz < 72 and dx > 8 and dx < 72 and heightmap[index] - minp.y < 0 then
+				return
+			elseif heightmap[index] - minp.y < min_y then
+				min_y = heightmap[index] - minp.y
+			end
+		end
+	end
+	if min_y >= 72 or heightmap[3240] >= 72 then
+		return
+	end
+
+	local base_height = math.min(min_y, 35)
+
+	local csize = vector.add(vector.subtract(maxp, minp), 1)
+	local map_max = {x = csize.x, y = csize.y, z = csize.z}
+	local map_min = {x = minp.x, y = minp.y, z = minp.z}
+
+	local pyramid_1 = minetest.get_perlin_map(pyramid_noise_1, map_max):get3dMap_flat(map_min)
+
+	local write = true
+	local p2write = false
+	local caskets = {}
+
+	index = 0
+	local index3d = 0
+	for z = minp.z, maxp.z do
+		local dz = z - minp.z
+		for x = minp.x, maxp.x do
+			local dx = x - minp.x
+			index = index + 1
+			index3d = math.floor((z - minp.z) / 5) * (csize.y) * csize.x + math.floor((x - minp.x) / 5) + 1
+			local ivm = area:index(x, minp.y, z)
+
+			--pyramid_1[index] = math.floor(pyramid_1[index] + 0.5)
+			for y = minp.y, maxp.y do
+				local dy = y - minp.y
+
+				if dy >= base_height + 3 and dy <= base_height + 37 - math.max(math.abs(dx - 40), math.abs(dz - 40)) and pyramid_1[index3d] > 0 then
+					if data[ivm - area.ystride] == node['fun_caves:pyramid_1'] and math.random(100) == 1 then
+						data[ivm] = node['fun_caves:casket']
+						caskets[#caskets+1] = {x=x, y=y, z=z}
+					else
+						data[ivm] = node['air']
+					end
+				elseif dy >= base_height and dy <= base_height + 40 - math.max(math.abs(dx - 40), math.abs(dz - 40)) then
+					data[ivm] = node['fun_caves:pyramid_1']
+				end
+
+				ivm = ivm + area.ystride
+				if dy % 5 == 0 then
+					index3d = index3d + csize.x
+				end
+			end
+		end
+	end
+
+	if #caskets > 0 then
+		return write, p2write, caskets[math.random(#caskets)]
+	else
+		return write, p2write
+	end
+end