Giant clam
From Starfy Wiki
The giant clam is a large green clam found in a single level of Skydye Heights ("End of the Rainbow", Stage 6-2) in The Legendary Starfy.
The clam is surrounded by cotton candy plants, and occasionally opens and closes by itself. In the story, it contained a single rainbow droplet that was used to heal Papes and Ronk's wounds. Feeding the giant clam cotton candy while it is open reveals the rainbow droplet. If Starfy returns to Stage 6-2 after giving the rainbow droplet to Ruby, feeding the clam an extra ball of cotton candy causes it to explode and release many Pearls.