The Grim Adventures Of Billy and Mandy Episode 12 - Big Trouble in Billy's Basement / Tickle Me Mandy Episode Title:Big Trouble in Billy's Basement / Tickle Me Mandy. Big Trouble in Billy's Basement:After taking the Underworld's "Bad Book" from Grim, Billy becomes possessed by an evil presence. Then, Billy steals Grim's scythe, and uses it to open a portal to summon Yog-Sothoth. In consequence, Mandy calls for Hoss Delgado to battle Billy. It is revealed that the portal can only be sealed by throwing the book into it. As Billy eats the book, Mandy throws Billy himself into the portal, restoring everything to normal. Instants later, a portal opens up and Billy comes out and says they did not want him there. Tickle Me Mandy:Mandy and her parents leave the city for a day, which makes Billy feel lonely. Then, Grim uses his supernatural powers to create a fake Mandy with pieces of dolls and toys for Billy to play with. However, the "new" Mandy is too aggressive with Billy, and he starts fearing her. The next day, the real Mandy returns home, and promptly destroys the new Mandy while in the see-saw.