No, it's not a reference. Yeah, I don't get it either.
This weird blue guy is 3.75" tall with a 3" opening and can hold approximately 10 oz. On one side it features a purple inlay illustration of a hand holding a bunch of grapes, and the other side has the words "JOYCE those are GRAPES" on it.
Running ceramics through dishwasher cycles will severely shorten their lifespan, so hand-washing is preferred.