Asmall platform that transforms into a small turret when your hero walks onto it and deactivates when your hero walks off.
I have two ideas for this, it can either be a gnome shop item that can be bought and used once per level like every other gnome shop item or it can be level specific, perhaps in a future game in a dwarf level, yknow, this turret being another one of their inventions?
point and click to fire, upgrade to add poison effects, flame rounds etc.
got the idea from the pirate ship cannons in krf.