The thing is a random object that sometimes appears randomly in Universes. It is a can with a sentient gummy worm inside. This gummy worm is orange and yellow, and just sits in the can.
It was called "The thing" because creatures thought it would be too weird to literally call it a gummy worm in a can.
It was first found in 2739 OYC, and the last time anyone saw it was in 7698 OYC. It has never been found again.
This worm can also speak Russian quite well. No one really knows what it eats or drinks; some creatures think it doesn't even need to eat or drink.
For some unknown reason, the gummy worm has a strange attraction to this cereal made by some creatures on some planet in some universe called "Lucky Charms". It has been seen to eat the marshmallows in the cereal, and ONLY the marshmallows.