-2 defense is the equivalent of halving the stat, is it not? This produces a very slightly different number than listing the power as 500, which others have said is essentially Explosion's strength.

Obviously I don't want a discrepancy, I want the real number. Can anyone help?

(This is the first time I'm calculating the move in a situation where it may not OHKO a target, and the scenario where you'd want it to hasn't been brought up in one of Smogon's spreads. Every other time I've done the calcs, it was for Lickilicky, and the numbers are so sick it just boils down to "target dies" and a discrepancy is irrelevant.)

I've heard the subroutine is actually halving the defense, not lowering it by two levels. I'm not 100% sure on that, but I think that's what it does.

Edit: Smogon's entry says this:

Damage is calculated as though the defender has half of its Defense.

Okay, thanks. ..and I actually remember doing that for a lot of calcs, so I should have remembered <_<

A stat being lowered by two levels is not 50%, IIRC. It's some formula that's completely different from raising levels. If I had to guess, I'd say 50% is a four-level drop, and a six-level drop is ~67%, but that's off the top of my head.

But yeah, Explosion doesn't apply defense drops to the opponent. What it does is unique to the move, along with Self-Destruct, I believe. If the opponent were to survive the attack, its defense would be reset to the amount it had before Explosion, as an example.

A stat being lowered by two levels isn't always 50%, but it is when you were at either 0 or +2 to start with. A simple rule of thumb is this:

+6 = 8/2
+5 = 7/2
+4 = 6/2
+3 = 5/2
+2 = 4/2
+1 = 3/2
0 = 2/2
-1 = 2/3
-2 = 2/4
-3 = 2/5
-4 = 2/6
-5 = 2/7
-6 = 2/8

This applies to all stats, except accuracy and evasion.

Ah, I see, you basically flip the numerators and the denominators when you change from positive into negative. Seeing that symmetry helps.

[QUOTE USER="shadianvise" TIME="1263164160"] If the opponent were to survive the attack, its defense would be reset to the amount it had before Explosion, as an example.[/QUOTE]

Well, duh. I knew it wasn't a permanent thing; I had just temporarily forgotten the "literally halves defense" and instead was trying to find a way to get the equivalent through other means.