Now I'm all for recycling cells for crowd scenes (such as the barbarian being in the congregation at Eric's coronation) but I think having a bogbeast wearing the same frock and wig that a bogbeast Eric wore earlier on when one of Presto's spells backfired is a little silly. But nonetheless we have a frocked and bewigged bogbeast standing to the far right. The what must be purposeful inclusion of this makes no sense.
Maybe when Presto conjured them off of Eric with his next spell rather than disappearing they were conjured onto some unsuspecting bogbeast who took a liking to this new fashion?
The only difference in the animation is that the latter frock doesn't have a red collar but a white one.