diff --git a/TODO.txt b/TODO.txt
index a05f351..0251b35 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,3 +1,3 @@
 
 TODO:
-- add lifetime limit
+- add option to remove mobs that aren't near any players
diff --git a/init.lua b/init.lua
index 8271833..a9bafdb 100644
--- a/init.lua
+++ b/init.lua
@@ -114,6 +114,8 @@ def.on_activate = function(self, staticdata)
 	self.knockback = false
 	self.state = math.random(1, 2)
 	self.old_y = self.object:get_pos().y
+	self.lifetime = sneeker.lifetime
+	self.lifetimer = 0
 
 	local data = core.deserialize(staticdata)
 	if data and type(data) == "table" then
@@ -135,8 +137,17 @@ local function isnan(n)
 end
 
 def.on_step = function(self, dtime)
+	-- update lifetime timer
+	-- FIXME: this is longer than realtime
+	self.lifetimer = self.lifetimer + dtime
+	if self.lifetimer >= self.lifetime then
+		-- TODO: should have a death animation
+		self.object:remove()
+		return true
+	end
+
 	if self.knockback then
-		return
+		return false
 	end
 
 	local ANIM_STAND = 1
@@ -339,6 +350,8 @@ def.on_step = function(self, dtime)
 	else
 		self.object:set_acceleration({x=0, y=-10, z=0})
 	end
+
+	return true
 end
 
 def.on_punch = function(self, puncher, time_from_last_punch, tool_capabilities, dir)
diff --git a/settings.lua b/settings.lua
index 979315f..8c0a19a 100644
--- a/settings.lua
+++ b/settings.lua
@@ -3,6 +3,13 @@
 
 local time_min = 60
 
+--- How long (in seconds) sneeker remains in world after spawn.
+--
+--  Default: 15 minutes
+--
+--  @setting sneeker.lifespan
+sneeker.lifetime = tonumber(core.settings:get("sneeker.lifetime") or time_min * 15)
+
 --- Loudness of explosion.
 --
 --  @setting sneeker.boom_gain
diff --git a/settingtypes.txt b/settingtypes.txt
index 82c886a..4e73b5d 100644
--- a/settingtypes.txt
+++ b/settingtypes.txt
@@ -2,6 +2,11 @@
 # Extra debugging messages.
 enable_debug_mods (Mod debugging) bool false
 
+# How long (in seconds) sneeker remains in world after spawn.
+#
+# Default: 900 (15 minutes)
+sneeker.lifetime (Sneeker lifetime) int 900
+
 # Loudness of explosion.
 #
 # Those with a weak heart might want to turn it down.