Based on an octopus, the Octus has a pink round head with large black eyes and a large purple snout. Below its head it has a gray and black disk with six ten mechanical tentacles attached, each with a gray suction cup at the tip.
At some point, the Octus joined a group of Mashers and Chop Chops to catch Sonic when he entered their underwater turf. However, they were all defeated when Sonic lead them into some underwater seaweed where they became entangled. This event was recorded for Robotnik's S.S.S.S.S. Squard to see.
- The scene in "Untouchable Sonic" where the Octus is seen is from the unaired pilot episode for the Adventures of Sonic the Hedgehog television series.