ZDoom

I don't think you're understanding. +THRUGHOST when applied to puffs, allows you to shoot through actors with the +GHOST flag. Ie. Hitscans ignore them and pass right on through. I'd like to have the same behavior for +MTHRUSPECIES when applied to a puff. The behavior is already there, I just would like it be extended to that. Not to mention, if applying flags to bullet puffs to influence the attack wasn't possible, wouldn't that make assigning damage types to bullet puffs impossible as well, when such a thing actually DOES work? (+THRUGHOST being another proven case.)

But puffs do not collide, so I don't really see how it would work. Presumably, what you want is for the hitscan attack to go through obstacles of the same species as the attacker, so the good place would be a flag in the hitscan attack function. The bullet puff is only spawned after the hitscan found a victim; by then it's too late to say "no, not this one, go further forward".

Pretty self-explanatory. I'd like to see +MTHRUSPECIES work on Bullet Puffs just like +THRUGHOST does. If that could be done, I'd be very grateful.