Kaminoan "super-weapon" project

An unnamed, "super-weapon" was commissioned by the Galactic Empire, sometime around the Battle of Yavin, for development on Kamino.

Characteristics
The creatures developed by the project was at least 6 meters tall, with thick, blaster-proof, black skin. The creatures were capable of rapid movement both on land and in water. Furthermore, the creatures were designed by the Kaminoans to be capable of transporting prisoners via an air-tight pouch in its stomach.

Encounter With Red Squadron
During Red Squadron's mission to Kamino, one of these creatures swallowed both Luke Skywalker and Lune Oddo Divinian whole, transporting them to an underwater cave serving as the creatures lair. Either this creature, or one of its identical brethren, met its match when Divinian dispatched it with Skywalker's lightsaber. Skywalker and Divinian then used its air-tight stomach to attempt to swim to the surface.

Encounter with Imperial Forces
During Red Squadron's escape from Kamino, twenty or so of these creatures disabled multiple Imperial aquatic tanks, dragging them down into Kamino's depths.

Appearances
Rebel Force: Firefight