18
It may not have been bad to you, but if I had kids, I wouldn't want them to see THAT scene! It's not just the nudity, it's the scene of a Goa'uld snake writhing over a naked woman and then punching through her back. Not only is it scary, but when you think about it, it could be seen a metaphorical for something else if you catch my drift "nudge, nudge". I don't watch it that often for the sheer fact that if a member of my family caught me watching it then they'd think I was a filthy pervert watching a porno movie! So I think the 18 Certificate is justified!