Hit Points or HP are described on B 327/380/419
One way to look at things:
Unliving objects have twice the HP of living ones. Homogenous ones have twice the HP of Unliving ones. Injury Tolerance (Unliving) is 20 points; Injury Tolerance (Homogenous) is 40 points. So roughly speaking, each doubling of HP corresponds to a 20-point trait. Now of course those traits don't actually affect HP, but we could posit that removing them from an object that has them would temporarily make it flimsier, so we could imagine that's Affliction with Negated Advantage, +20%, but we could call it Hit Point Reduction, +20% instead.
Normally, that would work just once, so if repeated uses stack, that's Cumulative, +400%. And duration is normally minutes, so if it's "permanent until healed," that's Extended Duration, Permanent, +150%.
There would still be resistance rolls aided by DR; to remove the effects of DR, add Cosmic, +300%.
So for 97 points, you could have an attack that cuts HP in half, round up, if the target misses a HT roll. I'd say it affects current positive HP; at 1 HP or below, it wouldn't do anything. Thus if a fighter with HP 16 were currently at 13 HP, the first zap would make it 7 HP, the second zap would leave 4 HP, the third would leave 2 HP, and fourth would leave 1 HP, after which nothing would happen. __________________