Immunity to fast-moving object/magic damage

As a GM in your system of preference, what house-rules / mechanics would you use to represent an enemy that is only affected by slow attacks (sharp/pointy objects moving as fast as 1 inch per second)? Someone trying to harm him should make a normal attack to bypass his dodge/parry/block/armor but suddenly slow it just before the impact in order to deal damage.

Just put some kind of penalty on attacks that could possibly work and say the others don't I guess. I would probably avoid bringing dune force fields into games in general though

That sounds like a pain in the butt to adjudicate. But probably say that characters can called-shots it with a given penalty, on attacks you seem appropriate? Just effectively raises AC, vs opponents who know how it works.

I wouldn't because that sounds convoluted as hell and the only difference would be they'd have to say "Okay I slow down right before I hit him" but otherwise do nothing different.

If you however do need an answer to your completely asinine question I guess some sort of damage resistance for objects that have to move fast (ranged weapons in particular). Regardless it doesn't matter because they could just do stupid shit like trip/grapple him to death.

Does that mean he can still die from fall damage?

No, falling speed is too fast for him to take damage

I will opt for the damage over time then. Dropping him in lava will do just fine? Or even death by drowning. I never tested this ideal with my dm before but could I summon bond weapon in his trought?

You could go full Dune and make the players learn a specific new type of combat style to purposefully slow their attacks against the shield. Your best bet is to do called shots like said.

tie him up and leave him somewhere that a slow-moving object will crush him to death

How big of a penalty on a d20 and 3d6 roll-under game?

do you have any idea how ridiculously slow 1 inch per second is, that is slow enough to dodge from a starting position of contact.

well, that's why he's so hard to kill

Attack penalty, immune to bludgeoning damage. Done.

>immune to bludgeoning damage
No, he is immune to everything moving fast

A slime with a frail core armored by non newtonian metal sounds like a good creature to use this rule on.

That's what I said.

You can't do damage with a slow moving fiat.

You can do damage with a slow moving knife or sword.

Attack penalty, immune to bludgeoning = immune to fast moving attacks.

You could still crush the guy or grind his bones, however.

Hmm. True.

Immune to bludgeoning damage from anything that takes an attack roll. If they roll reflex (such as to get out of the way of a boulder), that can still hurt them.

Still, fairly simple to stat up.

You would also want to throw in an immunity to projectiles. If you "slow them down" they don't work.

No he would be impossible to kill. He can just lazily move away from the knife coming at him at 1"/second. You couldn't even pin him because any grappling moves would be stopped by his autism field. A knife running along flesh at 1"/second would barely cut him. Stabbing at that speed would also do jack shit. Since he can just squirm around, and if the knife sped up at all it would be stopped by his autism field.

This whole thing sounds like a dumb idea.

it sounds like they'd have to find a way to immobilize it then just slowly stab it to death with a sword, which could make for a nice puzzle boss, but a shit enemy encounter