Ushabti

Ushabti are initially given to the player (25-50) depending on Slayer level and additional ones may be purchased from Slayer Masters for 20 slayer points each. The formula for the initial number received appears to be 25 + 1 for each additional Slayer level over 99, or 50 at level 120 Slayer.

They can trap the souls of slayer monsters used to fill up the Slayer Codex, and the Chest of Souls in the Sunken Pyramid.

Slayer monsters spawned inside a Sunken Pyramid cannot have their souls trapped.

Ushabti have a chance upon kill to trap a monster's soul inside. This chance is increased while on a slayer assignment for the monster .