Rat
Ground Zero was a team based out of New York, financed by - I think - Jerry Braun, who ran Paintball Sports Magazine and also owned a field in New York state.
The team had lots of talent on the roster - Nicky Cuba, the Lundqvist brothers, Dennis Mood, Robert Rose and Will Arroyo, and were quite successful in the late 90's/early 2000's.
They went through a number of roster losses and additions, notably the Blonksi brothers, and with the advent of X-Ball, they became New York Extreme but struggled to adjust to the fomat and eventually disbanded.
Hope this helps.