What would this look like?

[Zappo]

Warhammer Fantasy Roleplaying had some pretty good crit tables too. The best part is that, because of how the system works, every combat in WHFRP ends with a crit of some sort. So whenever you kill someone, you know exactly what organ you now have hanging from the tip of your sword.

 

[Vrecknidj]

If anyone did 250 hit points to a dragon in one hit, it would very obviously have to hit a vital spot (unless the dragon has something like 500+ hit points). I'm thinking a lance through the eyeball, or into the throat might do it.

Yuck.

Dave

 

[hong]

Then there was the 98 damage critical on a 4 hp kobold. "He's now a fine red mist".

Wow, that puts to shame the 125 point critical IMC on a 20 hp assassin.

Wrt the original question, what the attack looks like depends not just on the damage dealt, but also the target's starting hp. A 10 hp, 1st level fighter who gets hit for 20 points is dead as a doornail, whereas a 100 hp, 10th level fighter who gets hit for 20 points is lightly wounded and still going. Hit points represent your ability to translate what would be a lethal blow into a survivable one. The more hit points you have, the better you are at it.

The same principle applies to a 250 point hit; the numbers just scale up. A dragon with 750 hp (achievable for CR 20-ish monsters with tons of HD) would soak that damage, although it might not be laughing. It's only if you kill the dragon with that one hit, or reduce it to a small fraction of its starting hp, that spectacular visuals would be called for.

 

[Eosin the Red]

I am with Hong on this one (for once)

Doing 200 HP to a 800 HP dragon will likely only be something as simple as the lance biting between scales before it shatters.