They behave identically to "larger" monsters (such as MemBrain, Dinga, and Mama Guts). Mega Clotty slowly moves around the room while hopping occasionally. It fire 6 bullet shots around itself whenever it hops, but also can leave a small puddle of red creep. Rarely, it can either spawn a Clotty or even a collapsed Globin.
Though their sprite shows three fused Clotties, it always split into 2 Clotties upon death, not 3.