|“||Tac will fire his hand at you to try and steal your stat boosts. If he gets them, defeat him before he runs away or they'll be gone for good!”|
|— Tip • Super Smash Bros. for Nintendo 3DS|
Tac is a small, round yellow creature who wears black thief's clothing. The enemy sports sandals, as well as two catlike ears with blue interiors. Tac carries a green bag which features cloudlike white swirl patterns. The bag's design is consistent with traditional depictions of thieves in Japanese media. In Helper to Hero, Tac wears white garb and carries a red bag.
Tac appears as a common enemy in these games. He will run back and forth, occasionally jumping, and will attempt to steal Kirby's Copy Ability (or kidnap his Helper) by firing his hand forwards. Tac then attempts to flee from the scene with the stolen Copy Ability or Helper. To regain his Copy ability or Helper, Kirby must track down and defeat Tac. When carrying a Copy Ability or Helper, Tac cannot be inhaled and must be defeated with a physical attack. If Tac is not caught in time, he will despawn, permanently removing whatever he stole. If his escape route is blocked off, Tac may fly offscreen like a rocket to escape. Tac and Bomber are the only enemies to inhabit the planet ???.
Tacs are also seen in the intro of the sub-game, Spring Breeze where they are one of Dedede's minions who helped him steal all the food in Dream Land.
As a Helper, Tac differs greatly from Copy Kirby. Whereas Copy Kirby projects a beam to analyze and copy an enemy, Tac swiftly thrusts his hand forward, much like he does as an enemy, this damages the opponent just as if it was a punch. When guarding, Tac camouflages his body to blend in with the background, doing so negates any attack used against him, making them pass right through him. He can also perform Steal underwater. As a Helper, Tac is highly versatile, more so than Kirby or any other Helper. This is because Tac can take on the form of any other Helper when he copies the corresponding ability, which fully heals him in the process. When the Tac Helper takes such a form, his icon is marked by a "?" symbol, and he can discard the new Copy Ability and revert to regular Tac at any time.
Tac appears in Kirby Air Ride as an Event in City Trial Mode. When the event is activated, Tac will appear with stolen goods, mainly food and Patches. Running into him or attacking him will cause him to drop some items before running off. Tac does no damage if he collides with Kirby. Tac blasts off like a rocket when the event is over, and leaves behind a very useful "All" Patch that can be collected. If the player spins at Tac and hits him, the player will receive 3 random power-ups at the same time.
A Checklist challenge exists in which Kirby must steal 8 items from Tac.
In the Super Smash Bros. series
Tac appears in Super Smash Bros. for Nintendo 3DS’s Smash Run mode. He appears in a puff of smoke and uses his Steal attack against players. In addition to damaging them, Tac will swipe several stat boosts. If his attack misses, he dashes away and tries again. Like in the Kirby series, Tac will rocket away with the player's power-ups if he is not defeated in time.
Tac also appears in Super Smash Bros. for Wii U’s Smash Tour mode. He will run on a path across the board, and will be defeated if touched by a player. When defeated, he will drop numerous stat boosts.
Tac appears as a trophy in both versions of Super Smash Bros. for Nintendo 3DS and Wii U, being an unlockable trophy in the latter that can be unlocked by collecting all the CDs in the game.
In Super Smash Bros. Ultimate, Tac appears as an Advanced-class support spirit which can be obtained by fighting a timed battle against a team of speedy Villagers who can who deal damage by running into the player's fighter. His spirit, when applied, pulls items towards the applied user.
|“||This zippy character appears in the Kirby series. In Smash Bros., he'll appear in Smash Run to try to steal your stat boosts from you. How much he steals depends on how much you've improved your stats. If you can catch him, you can get whatever he stole. Don't give up!”|
|— Trophy description • Super Smash Bros. for Nintendo 3DS|
|“||This speedy little guy is from the Kirby series. In those games, he steals the ability Kirby's in the middle of using and bolts. If you want it back, you have to chase him down and take it. In Smash Tour, Tacs appear randomly on the board, and you'll be rewarded with multiple stat boosts if you're quick enough to catch one!”|
|— Trophy description • Super Smash Bros. for Wii U|
Tac's name is "cat" backwards. This references his physical appearance, his stealing actions akin to a "cat burglar," and his function as the enemy and Helper for Copy as a "copy cat." His name in Kirby Super Star, "T.A.C.," is also cat backwards, but is written as a pseudo acronym.
- In Kirby Super Star Ultra, Tac's usual "Steal" was modified to be a chargeable move; holding the button allows Tac to charge up and perform the "Cat Magnum," which does more damage to an enemy when fully charged. This makes Tac the only Helper to gain a new move in the remake.
- In Helper to Hero, Tac cannot copy abilities like he regularly can. Instead, the target is simply damaged when Tac's attack hits.
- In Kirby Mass Attack, Tac makes a cameo on the pinball table in the sub-game Kirby Brawlball. He can grab Kirby and move him to the center of the board. He will only appear if Bio Spark has been hit beforehand.
- Tac is the only Kirby series trophy to exist in both versions of Super Smash Bros. for Nintendo 3DS and Wii U to have different trophy descriptions.