User blog comment:Omega natsu2/Chapter 384: Surfing Lucy, Predictions./@comment-7418318-20140507091836/@comment-7418318-20140507105456

Especially with the total lack of any life-support systems. He's literally a naked brain in a glass jar.

While it would barely make any sense for Yachiru to be a Zanpakutou Spirit, it'd still make more sense than what we just saw about Gremmy...