The titan is a tank in WDL ThunderTanks. It is driven by Big Lenny. It's main weapon is a Mammoth F5 140mm Siege Cannon, it's special ability is being able to run over other tanks to destroy them. It seems to be featured on the box art for the game, albeit with a different paint scheme.
It is the only tank in the game that expels a shell casing when firing, owing to the large caliber of the round it fires. It is called "Goliath" in the GBC version.