Showderp is a wonderful time where we all pretend our champion is Marriland and try to convince opponents that that person is Marriland and/or close their window with CTRL+W. Showderp can be quickly assimilated into; just references these guidelines:

1) If the current champ leaves, a new champ is called (must be in an actual post in the current thread, not just in the battle chat), or the champ disappears for 15+ minutes, the first to claim themselves champ (anything from just quoting the call for new champ to just "me" or "kek"; tripcode highly recommended in order to thwart impostors) becomes new champ.
2) Once the new champ is called (or new team), the first 6 suggested Pokémon are used for the next battles.
3) Suggestions may not be skipped; the following takes place in the event of duplicates:
3a) Two calls for "gengar" in the first 6 suggestions: One Gengar is used, the other call is skipped in favor of the 7th suggestion.
3b) Two calls, one is "Blood waifu", the other is "Lilligant": Use the specified "blood waifu" set and skip the more general request.
3c) Two calls specifically for mega-evolutions: Champ gives the mega stones to each and decides upon battle which mega to use for the match.
4) Champ is free to call for a new team or champ upon having played at least two matches.
4a) Champ may also call for a new champ at any point if they have to leave for some reason. If an emergency, and the champ is in battle, it should be announced at the match forfeited if absolutely necessary.
5) Intentionally forfeiting, DC'ing and/or time-stalling are not allowed. Be a good sport. You will fight until your Pokémon or your opponent's Pokémon are KO'd. If for whatever reason you cannot finish a 30+ turn match without disconnecting, stop champing.

Pastebin for reference sets for new champs:
http://pastebin.com/fJUUWKtE

Current champ is: Foxx 5343-8934-0863, see >>16281671
Type /rooms [champ username]
in the showdown lobby to link to the champ’s battle.