The Treasure of Hillhurst Mansion - S1.E5

Flabber has a cold, and is surprised to discover that the old handkerchief he uses to blow his nose is actually a treasure map! The three Beetleborg kids use it to seek out what they expect to be riches beyond imagination. But Van and Trip swipe the map, in an effort to find the treasure themselves. The Magnavores then steal it from them, and release a monster, the Terror Bear, from the comics to keep the Beetleborgs busy. After defeating the monster, the kids team-up with the House Monsters to track down the treasure: and it turns out to be golden slime.