Circinus

This relic has a 25% chance of spawning a secret room in a given secret room, which is restricted to happening once per secret room.

It activates on the following floor from the one it is picked up on. Upon entering the next level a timer starts, and any rooms entered while the timer is active with an adjacent secret room will be revealed with a glimmer. Any discovered glimmer persists after the timer has expired.

It does not find crawl spaces.