Ethereal Jaunt. As a bonus action, a xill can magically shift from the Material Plane to the Ethereal Plane, or vice versa.

Poison Stinger. The xill injects poison into one creature it hit with its claws this turn. The chosen creature must make a DC 11 Constitution saving throw, with disadvantage if the xill hit it more than once this turn, taking 14 (4d6) poison damage on a failed save, or half as much on a successful one. If the poison damage reduces the target to 0 hit points, the target is stable but poisoned for 1 hour, even after regaining hit points, and is paralyzed while poisoned this way.