Friend Bandit
One who uses a friend as a middle man to other friends in an awkward, aggresive, and obvious fashion.
Natalie is suddenly always hanging out with my bestie Franny. She's such a friend bandit.
Best Friend Bandit
A person who has a new best friend every week. They typically go for those who give them the most attention.
"That girl is such a best friend bandit. She's with a new girl every week."
1: "I like your shoes!"
2: "Really? Wanna be my best friend!!!???
1: "I like your shoes!"
2: "Really? Wanna be my best friend!!!???