Jisuko

From Kokorodatabase

Jisuko is simply that cute little "myuah"-ing starfish that was actually discovered in an OOC chat between the authoresses, Plum and Jisu, while on an underwater adventure. After being saved by a shark, Plum decided to keep the starfish as a pet, naming it Jisuko, as a reference to Jisu. Now, Jisuko remains to be the pet of Shimizu Arisa in the Kokoro world, and has appeared randomly only to do things such as partying and dancing. The starfish also speaks only in "myuah"'s, and is only fully understood by Plum. It also seems that even to this day, despite being a part of the Kokoro world for many, many years, no one knows what Jisuko's gender really is.

And just for the sake of fun, let it be noted that Jisuko's first kiss was recieved by none other than Shirogane Ryou during a bet in which he had to kiss every living being presented in the cafe at the time.