User blog comment:Omega natsu2/Fairy Tail Episode 217: Celestial Spirit Beast, Review./@comment-5303512-20150124090331/@comment-25693405-20150124204643

I was thinking the exact same thing about the CSK. So far they've made reference too: It's parody though, so they shouldn't get sued. "Negima?!" did similar things and got away with it.
 * Princess Mananoke (CSK's design is a complete rip-off of the nightwalker)
 * Yu-Gi-Oh (Scorpio and Cana's Duel)
 * Pokémon (people are saying the sound when Juvia was turned into a constellation, plus Lily called Gajeel a "Ditto")