Nice drawing! Yeah, I can understand how it will work with a trenchcoat or some such. When you said spider-mutant I thought about a seriously hideously mutated Spiderman
Kinda like this: http://fc04.deviantart.net/fs51/i/2009/264/b/5/Mutated_Spidey_by_soulmaninc.jpg
Sylene was heavily inspired by Man-Spider, but I dialed it back on her so she could stay with the party and keep that group cohesiveness. Though, were she ever to drop to 0 refresh, she'd probably mutate even further and resemble Man-Spider more closely.