Today's CotD is Mankey from SV, the much-hyped about tech Lv X killer. Statwise, 50 HP is 10 below the common 60, +10 Weakness isn't too crippling, no Resistance is common, and :colorless to Retreat is cheap. Extra Punch of course is its Lv X killing attack; for :fighting:, you deal an initial 10, and if the Defending is a Lv X obviously, 50 more. Now, while this won't kill your "tougher" Lv Xs (ie, non-SP), with Lake Boundary or Lucario GL in play, Extra Punch has more than enough power to OHKO any SP Lv X card that's weak to :fighting:. Honestly, this is one of the few cases in which the Basic is much more useful than its evolution (Primeape), and being a Basic, can easily be teched into almost any deck as long as you have a way of paying for Extra Punch.
Modified - 7/10 (Basically a suicidal attack since Mankey isn't likely to live beyond getting the 1 KO, but he does do a number on Lv X cards for a very cheap cost)
Limited - 2/10 (Not much use here, as odds are you won't see any Lv Xs being used)
Unlimited - 1/10 (No use here)