Normally when you deal damage to your opponent, say with a 5|5 abomination, you'll see a 5 pop out above your creature and a -5 pop out on your opponent's hp bar. With an overdriven voodoo however, the attack of the voodoo pops out above it, but only the -1 pops out of the enemy's hp bar, even though they take proper damage.
I assume acceleration would be the same thing.
