Time Baby

The  appears in the episode, "The Time Traveler's Pig". He is from the far future that Mabel and Dipper accidentally transport themselves to. He appears to be starting a war and shooting laser beams from his eyes, thus destroying a city. In the credits, he forces Blendin Blandin to remove all anomalies that Dipper and Mabel cause when they messed with Blendin's "tape measure-like time machine". Presumably, he is the leader of the Time Paradox Avoidance Enforcement Squadron. A document in "Irrational Treasure" states that a "time devouring baby is trapped in a glacier in Antarctica". This may be a reference to The Time Baby. It is also stated in the document that the statues at Mt. Rushmore are robots that will be called into action to fight the Time Baby.

Physical Appearance
The Time Baby has a blue hourglass mark on his head (red when attacking the city) and red-brown eyes. His head is slightly bigger than his body. Also, he wears nothing but a diaper.