That preview video didn't make it look like it did much, barely cracked 1/8th of the life from 3 characters, at first I thought it was 'sharing damage' across all toons in the area but it is damage to random spots. It may be more lethal to people moving around the area as the more you move the higher the chance of being hit by it repeatedly. But that just tells me to walk out the nearest edge asap unless you have no other choice but to go the long way.