Rampage damage type question.

When the rampage bonusses are reached, how much damage do they do when they hit?

Does the damage have a type and does it scale in any way?

I can see the effects on the wiki, but there doesn't seem to be any information about the damage itself.

Not a damage type but a damage increaser:

the character gains the following stats:

1% increased Movement Speed per 20 Rampage Stacks
2% increased Damage per 20 Rampage Stacks

I'm asking about the effects that blast off and delete everything on the screen, when the bonuses are reached.

eg. "15 - A nova of spears that damage and stun surrounding enemies", and so on.

Any idea how they damage the enemies? It seems to do a decent amount of damage even as the content gets harder. Some of them are corpse explosion effect, but not all of them. Even so, corpse explosion effects are secondary damage source and have types and percentages associated. I'm wondering exactly what these screen effects are, and how the damage seems to continue to be effective on mobs, beyond the campaign and early maps.