Ninetales

Type Tier
Fire UU
Statistics
Stat
HP
73
349
Atk
76
250
Def
75
248
SpA
81
260
SpD
100
298
Spe
100
298
Name Item

Sleeper

Leftovers
Moveset
~ Hypnosis
~ Toxic
~ Roar
~ Fire Blast / Flamethrower

This is really one of the best things Ninetales can pull off. This works well if you can get some Spikes down (probably from Qwilfish since you're most likely playing Ninetales on a UU team). Basically status what you can with Hypnosis and Toxic, and thanks to the way poison works in GSC, when you think the opponent will switch, Roar them out. Poison and Spikes will do some damage if they don't get any Leftovers recovery since Ninetales isn't going to be hurting a lot of things.

Other Options

Ninetales works by trying to get the opponent to switch a lot and get some Spikes damage. Confuse Ray and Attract can aggravate enough to force a switch (especially if used in tandem). Iron Tail is super-effective on Rock types and can get a Defense down if you're lucky, hopefully forcing a switch. Reflect helps the team and boosts Ninetales's bad defense. It does learn Spite, but it can't use Substitute + Protect with it, effectively canceling it's usefulness.

Opinion

It's annoying as hell, but it's not going to kill things, and the extremely common counters to Fire-types hurts its stalling movepool. It can, however, put something in a position to get killed by something else on your team. Definitely not easy to use, and to be honest, the vast majority of the time it isn't worth it even if you can get it to work.

Counters

Any Water or Rock-type easily defeats Ninetales with super effective attacks and resistance to Fire; Ninetales is a bit too limited to do anything else. Blissey and Snorlax are the standard special walling fare. Generally, most things that don't fear a moderately powerful Fire Blast and have Sleep Talk work fine.