There should be an overdrive in which your tank self destructs, but creates a large explosion which destroys nearby tanks. It should have a 14 minute recharge time, so that it can only be used once or twice per game, but in the first 15 minutes of a game, charge at a random time (only once during this time frame, and different for each player), so that many players don't use it at the same time, causing chaos, and also rendering it un-useful. It should not damage teammates.