Don's attacks are identical to those of the regular Tonberry and Master Tonberry, although they do much greater damage. He counters every attack with a strong Karma, and on each turn takes a step forward. After taking five steps he will randomly attack a party member with Chef's Knife, which can be an instant kill. If an aeon is summoned, Don Tonberry will perform Voodoo where he generates a tiny image of the aeon and stabs it for heavy magical damage; this attack ignores Shell and can be only reduced by Focus and the Shield command.
Damage for Karma is calculated the following way:
Don Tonberry will drop weapons with status strikes and armor with status proofs, the Instant Death versions of these abilities being fixed. Its equipment drops provide a 6% critical hit chance bonus instead of the usual 3% (this is relevant to weapons and armor, but only to attacks that deal physical damage).
While fighting Don Tonberry, the player should cast Hastega on everyone and then get Don Tonberry to counter with Karma the character whose Overdrive mode is Stoic, then revive him/her with the other party members and recast Haste. The player should repeat this until Don Tonberry is dead or gets too close and the player is forced to flee. When Don Tonberry counters with Karma, the damage will fuel the Overdrive, which will triple and then convert into AP, and at the end of the battle the total AP is also tripled. The AP is received even if the player escapes the battle, or the Overdrive gauge is full.
It is possible to go from 0 to 99 Sphere Levels in one battle with three characters using this method; it is only limited by the party's MP and how fast Don Tonberry closes in. The amount of Overdrive received is determined by the amount of damage received which, for Don Tonberry, is the number of monsters a character has killed multiplied by 100. Only the Overdrive → AP ability is needed for this trick, but the other two abilities will boost the amount of obtained AP. The only character that needs to receive damage from Karma is the character whose Overdrive Mode is set to Stoic, meaning one can easily level up a weak character by skipping their turn and having a strong healer and a character who has had a lot of kills to perform the trick. Even weak characters can use this method.