Probabilitor is the leader of a group of mythical creatures and revealed to be the greatest wizard in all "mathology," give or take an error of 0.4. He succeeded in capturing Dipper and Ford, with some assistance from Hot Elf, an ogre and the griffin. He revealed that wanted to eat their brains so that he could gain their intelligence. He later challenges Mabel and Stan to a board game of Dungeons, Dungeons, and More Dungeons. During the game, the Probabilitor conjures different spells and summons various creatures that the humans fight against, including the Ogre-nado and the Impossibeast. In the end, he loses to Stan and Mabel, and is then whisked back to his home dimension, never to be seen again.
- Probabilitor's weaknesses are prime statistical anomalies over 37 but not exceeding 51.
- In the '90s during the period that the creators of the game tried to make it "cooler," Probabilitor's name was changed to Probabilitizzle.