Do you have a Sonic Drive-In near you? It might be time to go get a burger, because their Happy Meal equivalent currently has Madballs.
Solid-color water squirters or existing molds may not exactly float your boat, but they also have an exclusive Madball based on their cherry limeade signature drink:
Some locations will allow you to buy the promo toys separately, so you may not need to buy a kids' meal at all. Only one way to find out!
As a bonus, here's the art of Cherry Limeade, as well as Hate Skate, another original character who only appears in the sticker set (Sonic is a drive-in restaurant and uses rollerskating car hops to deliver your food):
