I'm sad that we won't be watching more of the Impel Down arc for a while, because episode 425, "The Strongest Man in the Prison! Poison Man Magellan Appears!" reminds me of everything I like about One Piece.
The chase scenes that made up the early part of the episode had me rolling with laughter, reminding me of the Tom and Jerry or Wile E. Coyote cartoons I grew up watching. Buggy's ability to come apart lets him bounce back from all kinds of crazy injuries, letting the slapstick violence and wild takes flow freely. From the hippo who can run but can't turn to the praying mantis who spends more time showing off than fighting, the chases are comic gold.