Evil Librarian by Michelle Knudsen
"When Cynthia Rothschild's best friend, Annie, falls head over heels for the new high-school librarian, Cyn can totally see why; he's really young and very good-looking. But after meeting Mr Gabriel, Cyn realizes something isn't quite right. Maybe it's the creepy look in the librarian's eyes, or the weird feeling Cyn gets whenever she's around him. Before long Cyn realizes that Mr Gabriel is, in fact ...a demon. Now, in addition to saving the school production of Sweeney Todd from technical disaster and trying not to make a fool of herself with her own hopeless crush, Cyn has to save her best friend from the clutches of the evil librarian, who also seems to be slowly sucking the life force out of the entire student body!"- summary from Amazon
This was such a fun and witty book; it reminded me a bit of Team Human by Sarah Rees Brennan and Justine Larbalestier. I wish there was more humorous paranormal YA. Knudsen did a wonderful job writing some humor into a normally dark subject, though there was still plenty of dark and creepy things going on.
FTC: Received ARC from publisher. Link above is an Amazon Associate link; any profit goes toward funding contests.