Piccy!
This is the Stabbing attack for Dragon Knights, and should ONLY be used with Spears.... if you're hoping for some good damage/a training skill, that is.
Crusher deals 170% damage nine times when maxed, so its knockback rate is less than if you used Dragon Fury. This is because the damage needed to knock back a monster does not stack, so it goes by the highest number that you see on your screen.
The skill progression goes like this:
Very little damage --> Lots of damage
and [the important part]:
Start: 1 monster, 2 hits [level 1~5]
---> 2 monsters, 2 hits [level 6~11]
---> 3 monsters, 2 hits [level 12~15]
---> 1 monster, 3 hits [level 16~20]
---> 2 monsters, 3 hits [level 21~25]
---> 3 monsters, 3 hits [level 26~30]
So, from levels 1~5, you might as well use Power Strike, since Crusher does only half the damage that power stike would do.
From levels 6~11, Crusher overpowers Power Strike:
Level 6 Crusher: 80% x 2 monsters x 2 hits = 320% damage.
Level 30 Power Strike: 260% damage.
Levels 12~15 are pretty cool.
At level 16, crusher drops back down to hitting one monster at a time. Thus, the damage is MUCH less, and the mobbing points are lost.
Level 15 Crusher: 120% x 3 monsters x 2 hits =720% damage.
Level 20 Crusher: 140% x 1 monster x 3 hits = 420% damage.
So, I advise any DKs looking to go for crusher to save up points over the 3 monster/1 hit period.
At levels 21~25, you'll be feeling good.
However, three hits vs. two hits... two hits wins in speed, by FAR. You'll notice the change immediately. Even though, you'll get used to the three-hit speed in no time!
At levels 26~30, you'll finally be getting that pr0 feeling, and at level 30, you will feel like a GM. [aka, even more pr0.]