Calavera (Spanish for "skull") is the midboss of Spooky Trails in Mario + Rabbids Kingdom Battle. As his name suggests, he is an undead Rabbid with Day of the Dead attire, including an old top hat and an elaborate skull tattoo on the back of his head. He sits within a large, dilapidated wooden coffin, threaded with large, spiked vines that act as limbs. One vine carries Rabbid Yoshi for use as a weapon (although his portrait sprite depicts him holding a bomb instead), while another holds the coffin lid as a shield.
Calavera acts much like a Buckler, with his shield making him immune to weapon attacks from the front. His main attack involves him shaking and then squeezing Rabbid Yoshi, who then spits out a Grenaduck at heroes. Any Mega Blocks caught in the blast will be damaged. He can also force heroes to move away from him with a massive scream. Altogether, he makes it difficult for the heroes to stay in cover, which can leave them vulnerable to Calavera or his backup, which includes Spooky Ziggies, Smashers, and Peek-a-Boos.
When defeated, Calavera falls into a nearby well, and Rabbid Yoshi shoots him repeatedly.