This handkerchief-sized black circle becomes a great hole when placed on a flat surface.
Wondrous Item 105,000 gp
Power (Standard Action)
Place a portable hole on a wall, a floor, or a ceiling. (The surface must be flat for the item to function.) The portable hole instantly creates a 5-foot-wide, 5-foot-deep hole in that surface. With a standard action, any creature adjacent to a portable hole can pick it up, provided there are no creatures or objects inside it.
Published in Player's Handbook, page(s) 254.