diff --git a/data/mods/experimental/init.lua b/data/mods/experimental/init.lua
index c37488d0425bd059cd424e8c63ed6786f26db3aa..5f01d8b78815b4c979037e09d84ca12ec371c3d4 100644
--- a/data/mods/experimental/init.lua
+++ b/data/mods/experimental/init.lua
@@ -330,7 +330,7 @@ function TNT:on_activate(staticdata)
 	self.object:setvelocity({x=0, y=4, z=0})
 	self.object:setacceleration({x=0, y=-10, z=0})
 	self.object:settexturemod("^[brighten")
-	self.object:set_armor_groups({foo=1,bar=2})
+	self.object:set_armor_groups({immortal=1})
 end
 
 -- Called periodically