tbh the first time i remember seeing cele was on eo's mixken stall like round 3 or 4 bw ou suspect. i feel like that squad also harbored the intro of sdef rachi, good work (BAN ME PLEASE). he was rockin tink with np / giga / hpfire / recover (modest with speed for tar, rest in hp) and while three attacks had some success as a sweeper and lure for things like tran and dnite, the former remained the standard until bw2. at the time it cockblocked drizzle pretty thoroughly, gave u a win condition vs the garbage glisferrojelli stalls being especially nice for setting up all over ferro, and foiled scizor + rotomw while not being so vulnerable to sdef tar pursuit (scarf was nonexistent). to elaborate on the stall matchup, when supported correctly there was very little stall could do (you also saw rain stall becoming hipster from eternal at that point and then seriously trending) to prevent it from outlasting them and sweeping. for example,
www.youtube.com/watch?v=T8uIFVuMXHc yes kovin pls. as a bw1 side note, bulkier like str8 walling sets were not rly seen until the metas final stages on things like krack/oristeros/bkc/ojama/whatever cunt stall with teams like this being the main standard
http://www.smogon.com/forums/threads/toxic-invasion-peaked-1st.3463227/. altho shoutsout k-12 the madchine with the first psonger which i believe was mainly to shut down bulky cm reun (actually a big deal, some thought this could potentially be uber at the time lol, ud uturn with cbzor or pursuit futilely with mixtar and just be fucked) as seen here
www.youtube.com/watch?v=onQjD0Fg1fU
i kinda went off on this so edit for completeness sake: as bkc said, uturning bulky offensive sets were common on volturn mid to late bw1. it was basically just uturn over np to abuse it's pivoting while not losing momentum since its coverage was much more readily checked once np became a metagame staple.
so when genesect and torn-t were introduced, it kinda died down in usage, but after those bans it came back as a specially defensive pivot often seen on rain/sand offense to stall to cover keldeo and special lando (as well as general water spam and the buffed up breloom) evoking ebelt hp bug keld and all out attacking uturn land to shit on that in response. a little later, np + bp gained ground on rain offense with scarfkeld being a particularly threatening recipient, but i think heist was the true pioneer of that strat way back in bw1 when he had a team with it around a scarf toed/specs empoleon/torn core, not super practical but just devastating when executed. then even with lando banned which had made sdef almost a liability for a while, it never returned to that pinnacle of usage and you often see it needing to be supplemented for keldeo, for instance with jellicent on that bkc stall team (scarftar/tran/cele/jelli/lando-t/forre), being relied on more for its scald tox sponging on sand as well as perish.