The twenchok was an amphibious cephalopoid native to the water world of Sedri. It had eight tentacles, of which it could use four to move across land, and four eyes spaced around the top of its head. Though normally black, it could camouflage itself to sneak up on prey. It was equipped with a defense mechanism that shot quills; if attacked, it would retreat while firing these. Some were known to sneak into Imperial aquatic garrisons on Sedri.
- Battle for the Golden Sun (First appearance)