This is a tricky one as Chupa-thingies are tough to get above to do the Frog Slam (green power up) on and they tend to be grouped with around 1 or 2 more of them so dodging and keeping track of who you've hit can be hectic. They do change their positions however so you can get above them if there's a ledge somewhere nearby. So make sure you ONLY USE THE FROG SLAM to kill them. It will take a few tries but eventually you'll be able to defeat them eventually.