This rather expensive underwater toy called the RC Manta Ray is a sort of manta ray shaped submarine.  The remote control has two triggers, one for each thruster on the vehicle.  The thing I thought was coolest about the Manta Ray was that it can do barrel rolls and complete underwater loops.  That's pretty impressive.  It also glows underwater with its LED lights.  The Manta runs for thirty minutes and four hours to charge.  Only use it in freshwater, not saltwater.  Someone comment and tell me why the hajeebies I can't use it in saltwater.  Anyways, it's 119.95 without the nine volt battery and four AAs.  Yeesh.  Bit expensive I would say.