The aptly named Ping-pong tree sponge (Chondrocladia lampadiglobus) is a carnivorous sponge. Those ping-pong ball looking things are covered in tiny spicules which the sponge uses to catch tiny crustaceans.
I am obsessed with kelp forests! Since I was too young to realize the ocean wasn't doing so well. I was young I mean 2 years old! I credit this early love for kelp forest my bloom of love for the ocean I can't stop thinking about!