Ankirons resemble huge armored turtles with cannons sprouting out of their shell. In fact, Ankirons are so huge and heavy that all they can do is turn in place. Ankirons fire bombs at Wario, who can throw the bombs right back. They explode after a short time, however. Ankirons can also hide in their shells to protect themselves against Wario's powerful punches. If Wario continues to punch a protected Ankiron, it comes out (though still not harmable) and fires its ammunition (depending on species) in all directions.
Other varieties of these enemies include Skeletal, Circus, Ice, Bullock, Stuffed, and Mummy Ankirons. Aside from looks, Skeletal, Circus, and Ice Ankirons behave exactly the same way as normal Ankirons. The Stuffed variety can fire many bombs at once, while the Bullock and Mummy Ankirons shoot flaming bombs that damage Wario on contact until they cool off. However, the Bullock and Mummy Ankirons behave differently when they're attacked while protected, with the latter firing fiery bombs, while the former only fires normal bombs.
Wario also comments that they smell like feet in the official American Wario World instruction manual.