Thwack

Thwacks are box enemies with faces that live on Thwomp Volcano during the events of Mario & Luigi: Partners in Time. In fact, Thwacks are very similar to Thwomps in appearance and mannerisms. As such, Thwacks may be a sub-species of Thwomp or a separate (but closely related) species. Thwacks come in two colors: Red and green. Red Thwacks have blue eyes while green Thwacks have yellow eyes. Thwacks also make a variety of facial expressions.

In battle, Thwacks employ a variety of attacks. Before each attack, a Thwack will twirl and either remain the same color or change into a different color. If green, the Thwack will attack Luigi; if pink, the monster will attack Mario. After twirling, the Thwack may attempt to crush the Bro. of its choice. As the Thwack hovers over the hero, the baby Bro. should counter with a Hammer strike. Additionally, Thwacks may fly low, attempting to ram into a Mario brother. In this case, Mario or Luigi should jump to dodge or counter the attack. Thwacks can also summon more Thwacks to join the battle.

Occasionally, the Thwack may turn yellow (instead of red or green). When this happens, the Thwack will attempt a suicide attack in a last ditch effort to destroy the Mario Bros. After turning yellow, the Thwack will split into two boulders, and each rock will roll into a brother. This attack can be easily avoided by jumping.

Thwacks are close relatives of Wonder Thwacks and Thwack Totems (which are formed when multiple Thwacks merge into one entity).

Trivia

 * The Thwack's expressions are the same used for Super Mario Galaxy 2's Tox Box.