Peppermint Hippo Lost & Found is a side mission in the video game, "South Park: The Fractured But Whole".
Plot details follow.
Find Jimbo's wallet.
Jimbo will tell you he lost his wallet. He needs your help finding it. Go to The Peppermint Hippo. The wallet is located on a table to the left of the stage.
Return the wallet to Jimbo to unlock the Ham Radio summon. Use this to call in Ned and Jimbo to deal massive damage in battle.