Htextra
htextra is the amount of damage to be incurred by the weapon that is currently hitting the actor in question.
Example:
getactor[THISACTOR].htextra TEMP
If the actor in question is a useractor enemy, it will not count damage higher than the actor health.
sets TEMP to the amount of damage THISACTOR will take from the weapon currently hitting it. This amount can be modified before the actor actually takes any damage. If you want to no damage be taken, set to -1, not 0.
This can be used to decrease the amount of damage a certain actor get from certain weapon or enemy. ifhitweapon and ifdead seems to return if this value is positive. In other words, this can easily be used for an enemy takes damage, for example, in lava floors.