Some of the summaries for pokémon are delightfully snarky. Take, for example, the entry for Castform, whose only set offered is... "Everybody Look At Me I'm Using Castform". Made even funnier by its additional comments.
"Other Options: You can literally run any type of Hidden Power! Unown has an option for every type and its power knows no limits—other than being hit by any other opposing Pokemon, of course. Unown wouldn't want to learn any other moves anyway, because it does not need them. Hidden Power is all it needs to wreak havoc, cause despair, and spread fear amongst the opposing team. Using stronger moves such as the boring Fire Blast, Hydro Pump, or Draco Meteor would make Unown a little girl who can't fight and likes to risk a miss that could cost you a game. Unown is no gambler."
"Choice: This is your standard Choice sweeper. With Bug Bite, Kakuna is not walled by the likes of Steelix and Steel-type Arceus. As a matter of fact, Bug Bite's addition lowers max HP / max Def Steelix from a 94HKO to a 36HKO. Max HP Steel-type Arceus is now a 25HKO, while min HP/Def Psychic Arceus is a 22HKO.
The 2013 April Fools' Day joke had the sprites used on the simulator replaced with fanmade sprites made by the community...but this being April Fools' Day, the sprites were incrediblyOff Model. And the ones that weren't just blatantly Off Model often were either drawn in chibi style or contained Shout Outs; the number of references the artists managed to sneak in just boggles the mind. It has to be seen to be believed.
For April Fools' Day 2014, not only did Pokemon Showdown! add Kalos sprites, but each April Fools' Day sprite got a shiny version, with some shinies having an extra layer of humor. That's 3,734 new shinies!
"(Pokémon) used FISSURE! ...Just kidding! It was Earthquake!" The whole SCREEN also shakes for the animation. Even funnier than that is what would happen if you used Taunt or Metronome.