Originally Posted by Fat Gothic Togekiss
But what happen's if this thing doesn't get Megahorn? How much attack does it require to 2HKO Blissey with X-scissor?
Megahorn = 180 BP (after STAB)
X-Scissor = 120 BP (after STAB)
that looks to be about 300 Atk. Of course, this is actually a little higher, since BP is worth more than the attack Stat.
Or not. Changing the Atk to 300 and the BP to 120 returned the exact same percentages. This requires 130 Base Attack to achieve with minimal EV investment. In other words, this thing needs Megahorn or a 100 BP Bug-type Cross Chop. Or Attack Order... Hm... Atk need with Attack Order is 260 Atk, which corresponds to 110 Base Attack for minimal EV investment. A 100 BP move would require 230 Atk, which corresponds to either 95 or 100 Base Attack.
Just a little disclaimer, I am assuming Max/Max+ Blissey. This is rarely used anymore, so it might deal marginally more damage in practice.