EMP grenades do the following:
*Confuses the trash ,and Gorefast, ZEDs, making them walk into walls and such, unable to attack.
*Slows movement of some of the larger ZEDs and stops special attacks during the effect (Bloat's puke, HUSK's fire weps).
*Stops rage on the Scrake with 1 grenade for the duration of the flashy electric effect; once the effect ends it will still rage.
*Stops rage on the FP with 2 grenades. The moment the effect ends, any damage will contribute to it's rage.
*Minor damage to all ZEDs, can just about kill a Crawler if it's caught near the middle.