Oopart of the Ninja Mansion - S2.E14

After a hard night of training, Rich and Hyde sneak off into the ninja mansion in search of the OOPart. Geo also sneaks off to try to find it. Along the way, Rich and Hyde encounter the ninja instructor and transform to battle with him. Geo also transforms and discovers the OOPart, only to be attacked suddenly by Rogue. When Yeti Blizzard and Mega Man bring their OOParts close to the one in the mansion, a portal to Mu opens, and Rogue escapes into it. As it closes, Yeti Blizzard and Dark Phantom escape, the latter taking the OOPart (The Star of Ninja) with him.