Quagsire, with its many useful resistances and one (two with water absorb) immunities make it an amazing Switch forcer. A nice niche pivot on teams that abuse entry hazard.
Evry I make e'm shufflin
If your team likes entry hazards and the opponents spinblockers are out of the picture (or were never in the picture to begin with), Quagsire can make great use of them as a status/shuffler, forcing multipule switches and keeping the opponent on their heels.
Yawn is the key of this set, once you've snet in Quaggy against something it can wall, or if your running water absorb, an incoming Scald. It forces a switch, or if your opponent is feeling ballzy enough, gives you a free turn to switch to a counter, or another spiker and set up more entry hazards. Be warned however of scald's burn chance, athough it can be useful, It can quickly turn the orignal derpfish into dead weight.
Other options for the final move are aplenty
EQ, for the obligatory stab and a bit of a mixed attacking set to scare off the reeeealy frail sweepers who try to get rid of quagsire and set up afterward.
Bulldoze is an interesting option that can give you another turn to recover, and gets the same coverage as EQ, but with much less power
Encore rocks as well
wow, I might actually try using quaggy after this XD