Pop

match three to pop. cut the rest loose into the bath.

a bubble shooter in a bathtub: aim the rubber duck, match three, and drop whatever hangs below

Three or more of a colour touching pop. Anything left with no chain of bubbles up to the ceiling falls into the bath, and a falling bubble is worth far more than a popped one, so the best shot is the one that cuts a big mass loose.

Concepts: gravity, support, clusters.

An interactive you play with one thumb, on Wundr.