Janus creates a portal in the world. If placed on a wall, the portal will create a passage through to the other side of the wall that Janus or any ally may use. The portal may be entered from either side, but closes after 1 use.
If placed on the ground, enemies and Janus will fall into the portal, being teleported into the air above it. Enemies take damage upon landing, and are considered banished during the fall.