OU when?

At least wait for Reshiram

I remember being on Serebii forums in 2011 - under a slightly less autistic screen name - claiming Zekrom should be tested for OU because of its nonexistant movepool.

I doubt he would be balanced now, but I wouldn't mind playing a few battles with it in it just to see.

It 2hkos the entire tier bar ferrothorn and any ground type that's capable of outspeeding and killing it can't switch into its dragon stab