Episode Title:Is Another Mystery / Marco Jr..Episode Description:Is Another Mystery: Marco comes across a message from Buff Frog that he's leaving Mewni along with his children and other fellow monsters, so Star and Tom venture to his swamp where he tells them that there's no room for them on Mewni anymore due to the discrimination of their kind escalating. Although they try to persuade them otherwise - including Tom expressing his half-monster heritage - Buff Frog ultimately decides to depart, but reassures Tom and Star that he will stay vigilant if he is ever needed by them.
Marco Jr.: Marco and Star return to Earth to find out that he will soon have a baby brother named after him. He soon has a Mewni painter paint a portrait of him as a present to his new sibling, but the painter gets his image wrong, and the distorted magic painting disfigures him.