While at lunch with coworkers, I was looking at an Ebisu beer flyer and noticed something odd: the katakana began with ヱ. But I've never seen that character before!
As it turns out, it's an obsolete character for 'we'. In this usage, the 'w' sound would be dropped, meaning that ヱビス would be pronounced the same as エビス. Even weirder is the hiragana form of the character, ゑ, which looks like 'ru' but with a full loop and some flourishes!
If a 'we' sound is needed for foreign words, ウェ is now used. Oddly enough, that's exactly what we were taught in class.