Capes are essentially useless and create a lot of drag, although they look great. Think of a way they could be useful.
So far this is best I could do:
1: The cape is electric, touching it will shock foes.
2: The cape is telekinetic, you can take it off and wrap stuff with it telekinetically. Although that almost defeats the purpose of ever wearing it. Unless your lazy about telekinesis.
3: It makes you invisible when you cover your chest up with it.
4: It goes intangible so that a person pulling it won't get an advantage.
Anything else you guys got---I'm all out. And by cape I mean a normal one, not like the batman cape.