Cooler monster

The Cooler Monster is a creature that Dipper finds in the ice cooler at the Dusk 2 Dawn.

It is unknown whether this is an independent creature or simply a creation of Pa and Ma's own design. The latter is more likely, as the cooler monster is gone when Dipper checks the ice cooler again.

Appearance
It resembles a human brain with veins that form hands, two retractable stalk eyes and a mouth that looks like a pair of dentures. It is possible that the veins are actually the human nervous system as it stems from the brain.