Kingdom Hearts 358/2 Days
Though not seen, it is mentioned by Saïx when he planned to send Xion to deal with it during her time unable to wield the Keyblade, and Roxas to slay a Bully Dog. Axel was later sent to "keep it out of trouble", and describes himself as "[falling] on [his] butt chasing it around".
Roxas is sent to eliminate an unidentified giant Heartless that has surfaced in the desert and seems to be the source of Agrabah's mysterious sandstorms. When he arrives at Agrabah, he encounters this Heartless and quickly defeats it.
The Antlion is a massive, seemingly mechanical Heartless with a round, egg-shaped body comprised of several rotating rings. Each of these rings are white with black and yellow highlights, and each is lined by multiple, rectangular pillars. Most of these pillars are steel blue, though two on the first ring are a patchwork coloration of gold and copper. The Antlion's rear sports a grey turbine that it uses for locomotion. Its neck is black and gold, while its comparatively small head is roughly spherical and white. Its head sports glowing yellow eyes, a large, jagged mouth, and two short "horns". It also has two large, steel blue and gold mandibles on the sides of its head. Its Heartless emblem is between its eyes.
This Heartless starts out traveling half submerged in the sand. If at a distance, it is best to attack it with Fire or Thundaga; otherwise, move in close, preferably just in front of the moving Heartless, and use powerful Blizzard magic, like high-level Blizzara. Eventually, it will escape by diving into the sand. When it surfaces, it will attack with narrow shockwaves of sand. These can be easily avoided by climbing on top of one of the ruins, or by standing on the far side of one. After a few waves, it will charge at Roxas. If he is on a ruin, the Antlion will charge right into it, and it will be stunned and vulnerable to attack. Eventually it regains consciousness and tosses cube-shaped bombs before it sinks back down and starts traveling in the sand again.
After it has taken sufficient damage, it rises out of the sand completely, surrounding itself with a protective whirlwind. It will move around the field, dropping cube-shaped bombs, which can be blocked or avoided. Before the bombs explode, knock them back into the whirlwind to cause damage. Additionally, it will try to ram into Roxas, damaging him with the whirlwind. This attack can be blocked or avoided. Once the Antlion sustains enough damage from the bombs, it drops its whirlwind shield and falls to the ground, stunned. Use this time to move in and launch Blizzard spells or attack its head. After it recovers, it reforms its whirlwind shield, and the process continues.
Starting from the second time it raises its shield, the Antlion will also attack with an energy beam, which should be avoided. When it charges its beam, a purple aura surrounds its head. Keep moving to the left or the right until it fires the beam to avoid it. Moving in close will also allow Roxas to stay out of the beam's range. Should Roxas hit low HP, do not hesitate to use the Limit Break. A good time to use it is after it drops its Aero shield. Be sure to heal periodically.