This set takes advantage of Carnivine's best stat, its Attack, and boosts it with Swords Dance before attempting a sweep. Levitate gives Carnivine a unique immunity to Spikes, Toxic Spikes, and Ground-type moves, allowing it to take hits, conserve more health, and afford more opportunities for it to set up a Swords Dance. Sleep Powder can potentially remove one of Carnivine's counters from the match, which can mean a sweep or a key threat eliminated.
Power Whip is Carnivine's main STAB attack, having an effective Base Power of 180 after the STAB boost, and it will be hitting like a truck even without a Swords Dance. Return is a generic powerful move, and garners good coverage alongside Power Whip, denting Pokemon like Arcanine, Leafeon, Scyther, and Swellow hard. A mono-attacker approach can be attempted with Substitute and Leftovers over Return and Life Orb, but it is not encouraged as mono-Grass is walled by quite a few of the top UU Pokemon, and without Swords Dance or Life Orb, Carnivine will not be hitting nearly as hard as it needs to be.
As it stands, Carnivine outspeeds standard Milotic and can OHKO it with a boosted Power Whip, or 2HKO with an unboosted one. An option for using Carnivine in a Trick Room team is to remove all Speed EVs, place them in HP, and run a Relaxed nature to become as slow as possible. Carnivine is not recommended on a dedicated Trick Room team, though, since after a Sleep Powder and a Swords Dance, it only gets one turn to use an attack. Synthesis is another option to use in the last slot to give Carnivine a means of easy recovery. On the other hand, Stun Spore can paralyze common switch-ins, such as Venusaur, Mismagius, Scyther, and Swellow (before its Orb activates). Once they are paralyzed, Carnivine can come in later in the game, Swords Dance, and sweep through the paralyzed Pokemon. Sleep Powder is generally superior, however, as it can completely remove a counter from the game.
Carnivine, like all offensive Pokemon, enjoys entry hazards to help gain KOs and do more overall damage to the opposing team. Omastar is a notable teammate because it can easily come in on the Fire-types, such as Arcanine, that plague Carnivine and set up any one of the three entry hazards. Rhyperior can also deal with Fire-types, while also being able to handle Bug-types, due to its natural physical bulk, and Flying-types, due to its resistance. In addition, Rhyperior can easily switch into Registeel, a common Carnivine counter, and set up Stealth Rock to aid in Carnivine's sweep. Most Water-types can sponge the Fire Blasts and Flamethrowers that are sure to be launched at Carnivine.
Offensively, Fire-types are an excellent complement to Carnivine. Arcanine can get a free Flash Fire boost on many Fire-types and draws out Pokemon like Milotic, who can be easily set up on by Carnivine. Arcanine also easily handles any Steel-types and can lure out and KO Pokemon such as Moltres with a Flash Fire-boosted Flare Blitz. Slowking is also a great partner offensively, as it can switch into Fire-types and set up Trick Room to remedy Carnivine's low Speed. It can also lure out Grass- and Electric-types for Carnivine to set up on.