Copied from an old Smogon thread: The 24 Def EVs ensures that Scizor's Bullet Punch is always a 3HKO and Jirachi's Iron Head a 4HKO. Ideally, you will not want to be facing Scizor when it used Pursuit, as that means your probably lost a Pokemon! However, Scizor's Pursuit is still a 2HKO on the Substitute which allows you to Substitute and Charge repeatedly. The heavy investment in Special Defense may seem excessive, but allows you to carry out the same procedure against a Choice Scarf Heatran locked into Dragon Pulse, as it will never OHKO your Substitutes. The Speed is necessary to outspeed Skarmory and kill it before it has a chance to do anything. Do not try to set up on Skarmory, as Charge Beam will fail to OHKO the Steel bird and Magnezone will be met with a swift Whirlwind or an extra layer of Spikes. The remaining EVs were placed into Special Attack to pack a bit more punch.