Cycloptopus

The Cycloptopus is a creature Ford Pines fights and captures in "Dungeons, Dungeons, and More Dungeons."

History
In "Dungeons, Dungeons and More Dungeons," Dipper was reading some pages about it in Journal 2 but then Ford emerges from the underground laboratory with a Cycloptopus wrapped around his forearm. He fights and later captures the creature in a jar, but it is released again when Dipper falls into the basement and breaks the jar, the creature attacks Ford again.

Appearance
The Cycloptopus is green colored, he resembles an octopus but instead of two small eyes he has one large eye.

Trivia

 * Although it resembles an octopus, it seemingly doesn't need water to live and it can also be kept in a jar.