The Secret Tunnel is a secret tunnel that Bonkers is protecting for some reason. It was first revealed in Season 1
Secret Tunnel
Mission 5: Pop Goes The BooBoo (formerly Pop Goes the GooGoo).Not much is known about the place as it is only shown in the mission except that behind the face-door (inside of the tunnel), there is a secret CLONC labotory.When the secret code is entered on the mouth of the stone face, a part from the Moshi Dance will play.