Rizvum-pattern Revenant
From Halopedia, the Halo wiki
lobbThe Revanant is a new Covenant vehicle, similar to Ghost. Has a passenger seat and a plasma cannon.
http://xbox360.ign.com/articles/110/1107237p2.html
"The Covenant have another trick up their sleeves, however. It's called the Revenant and it behaves a bit like a Ghost crossed with a Wraith tank. This two-seater can boost around and is rather agile, but it fires the massive plasma balls that the Wraith tanks dish out. It's pretty devastating, but it offers little protection for the rider."
Image: http://www.bungie.net/images/Games/Reach/images/screenshots/Forge_Bnet/inline/Reach_MP_Hemorrhage07.jpg