You get dumped on by a bucket full of HELLACIOUS BLUE PHLEGM ANEURYSM GUSHERS as a thoughtful but mischievous thank you gesture from John.
Your PRANKSTER'S GAMBIT plunges to an all time low. You cannot hope to defeat Egbert in a prank-off. He is simply the best there is.
Author commentary: Ridiculous prank aside, this isn't a bad way for John to leave behind some useful health-restoration items for Rose. At least this way it increases the chance she'll notice them. Let's also note that Kanaya just watched a bucket drop on Rose's head. This means nothing to us right now, culturally speaking. But this event will be dramatically recontextualized for readers later.