Emphatic Untamed Calamity/Astrum Limus

Astrum Limus is a Revengeance Mode-exclusive mini boss. It spawns after the Astral Slime Deity in the Goozma fight is under 50% in Revengeance Mode or higher.

Trivia

 * It's a reference to the Astrageldon Slime, a removed boss that has since been replaced with Astrum Aureus.
 * Its name roughly means "Mud Star" when translated.