Nabasu are known to exist in two life stages: demonlings and mature nabasu. Both have the following abilities.
Death Gaze (Su) Once per day per growth point (minimum 1/day for a demonling, 10/day for a mature nabasu), a nabasu can use its death gaze for a full round. Living creatures within 20 feet must succeed on a Fortitude save or gain a negative level. A humanoid slain in this manner transforms into a ghoul in 1d4 rounds under the control of the nabasu that created it. The save DC is Charisma-based. If the nabasu dies, any ghouls under its control become free-willed.
Plane Shift (Su) Three times per day a nabasu demonling can shift to the Material Plane, and a mature nabasu can shift between the Abyss and the Material Plane or back. This transports the nabasu and up to six other creatures provided they all link hands with the nabasu. It is otherwise similar to the spell of the same name (CL 10th for the demonling and CL 13th for the mature nabasu).