A powerful battle tank in Halo, that's most likely the deadliest weapon in the game. It has a cannon that shoots 90mm shells that can kill any infantry and most vehicles instantly, and also has a machine gun for close range. The machine gun was used by the driver/cannon shooter in Halo CE and 2 but was shifted to a passenger in Halo 3. It's much better than the Wraith tank, as it's faster (except if the Wraith uses its boosters), the shells are much faster, accurate and slightly stronger, and it only has one weak spot (the canopy that the driver gets into) unlike the Wraith which has two obvious ones. Naturally, it owns everything, and is so tough even a Spartan Laser can't destroy it one shot. Run!
The UNSC got a battalion of M808 MBT Scorpions and pwned several Wraiths and Scarabs in Halo.