The pact is a brown piece of paper that was made to stop the war between SpongeBob and Patrick. It says on the top the "Thumb War Anti Aggression Pact." It is signed by SpongeBob and Patrick with their thumbprints.
Role in the episode
In the episode, it is made to stop a thumb war between SpongeBob and Patrick. It is torn up by SpongeBob at the end of the episode so Patrick and SpongeBob can have a thumb war.