What in the world does this mean?

[sisterspeed]

As I was playing Late Night, I looked at my relationships and noticed this rather strange one. I have no idea what these purple rings around this sim's head mean. I've never seen this before (I've been playing LN since it came out) and can't find anything about it on google. Maybe I'm just not looking hard enough, or incredibly stupid, but what on earth are these?

http://i56.tinypic.com/2z9hb0z.jpg

[saeda]

It is your vampire's hunt target; bite that person and they'll enjoy the blood even more than usual.

[sisterspeed]

Ahhh thank you! I must have never noticed them before because I usually make my sim's needs static. That would explain a lot.