The werewolf transformation scene was done entirely with practical special effects using prosthetic makeup and mechanical devices. It took over six days to film.
D. Duckie Rodriguez jumped into the role of "Joey Ambrose" a mere 48 hours before principal photography began. The original actor cast in the role had an emergency that prevented him from continuing with the production.
Shiva Rodriguez: Most of the members of the key crew were attacked by werewolves in the opening credit sequence. Rodriguez as a werewolf victim happens later in the film.