The Soviet 1K17 laser tank looks like something out of Command and Conquer, but it was armed and operational during the early 90s, and it had US Intelligence totally freaked out.
The 1K17 couldn't actually vaporize wave after wave enemy armor, which is a bit of a letdown. Instead, it was designed to use its lasers to overload optical tracking systems on aircraft, blinding pilots at the same time. It had 15 individual solid state lasers, each of which used a 70 pound synthetic ruby crystal pumped by a xenon flash lamp to fire a laser pulse through clouds and inclement weather. There's no info about how effective the system was (which may have been why it worried the US), but if I saw one of these pointed at me, I'd be too busy running away to find out for myself.
Unhappily for the laser tank, the Soviet Union collapsed shortly after it entered service and the program was scrapped. The 1K17 itself was also scrapped, but someone spotted one in a military museum near Moscow, and you can see a bunch more pics in the gallery below.