From the Super Mario Wiki
Retrieved from "https://www.mariowiki.com/index.php?title=Old_Key&oldid=2873262"
The Old Key is an item found in Super Paper Mario.
After Princess Peach joins Mario's party, Merlon gives her the Old Key, which unlocks a nearby gate only accessible by flipping to 3D. Past the gate is the Flipside Outskirts, which leads to the next Heart Pillar.
Names in other languages