Knucklotec is encountered when Mario enters the sand flow directly beneath the Inverted Pyramid. When he appears, he is distraught over the loss of the kingdom's Wedding Ring, and believes that Mario to have stolen it. Along with Bowser's icy water attack, he is the cause of the ice in the Sand Kingdom, and when he is defeated all the ice melts away.
In battle, Knucklotec slams his fists into the ground; if he strikes an ice shard, he briefly writhes in pain.
Mario must then capture one of the fists with Cappy and use it to knock out Knucklotec while avoiding the faceted ice crystals he fires from his other fist. After hit the first time, he will slide his fists across the battlefield once; the fists travel parallel to each other. He will then slam his arms, causing faceted ice crystals to burrow partially into the ground from above.
Mario must then repeat the process once more. During the third phase, his fist-slide attack is slightly faster, and he has an additional attack where his arms lock onto Mario before clapping together multiple times.
After his defeat, Knucklotec will explode, releasing the Sand Kingdom's second Multi Moon.
- Knucklotec slightly resembles Andross and the Floralians since their body plan is a disembodied head with two hands at their sides, although the Floralians have a body of leaves below their head and Andross is made of flesh and his hands can be destroyed.
- Knucklotec is the only boss that can be defeated by capturing one of their own body parts. In his fight, you capture his hands to punch him.