T-55

The T-55 appears as the main battle tank of the North Vietnamese Army in Call of Duty: Black Ops.

Campaign
In Call of Duty: Black Ops, the T-55 is used extensively by the North Vietnamese Army, it appears in two levels: "SOG", and "The Defector". In "SOG," the player must use M72 LAWs and TOW missiles to destroy attacking T-55s. In the next campaign level, "The Defector", a T-55 appears in the streets of Hue, near the end of the level, destroying the M113 Bottom Feeder. The player must use helicopter gunship support to destroy the tank and proceed. A few more appear shortly before the PBR arrives extracting the player.

Multiplayer
Multiple T-55s appear on the multiplayer map Berlin Wall, alongside its American counterpart, the M48 Patton but are only used for aestethics.

Zombies
It is seen in Dead Ops Arcade when the player picks up the "Tank" Power-up and transforms into a tank that resembles the T-55.

Trivia

 * The T-55 uses the Flak 88's firing sound from Call of Duty 2: Big Red One.