basicly take this existing model : http://www.garrysmod.org/downloads/?a=showimg&v=76642_1
from this model download http://www.garrysmod.org/downloads/?a=view&id=76642
and give it true venom like attacks, like say, able to jump and maby do some fast zombie type of moves
id say test with fast zombie animations and attacks and then add some more attacks from other npcs
maby some opposing force gonome annimations and attacks (hes about the same size) and some attacks (but not the acid throw)