MysteryBerries in The Mysterious Rainbow of Colors
In The Mysterious Rainbow of Colors, two Pichu are collecting floating Mystery Berries deep in the forest. They discover a mysterious rainbow fog, which originates from a nearby cottage. Inside, they find a Meowth trying to make a rainbow with a concoction in a vat, but the rainbow drifts at the ground. The Pichu add their floating MysteryBerries to the vat, which allows the rainbow to arc through the sky as intended.