hostage selfie

1. A selfie of you and someone you pulled into the photo without their prior knowledge, consent, or expectation.

2. A selfie that you take by sneaking up on someone as they're taking a selfie of themselves, grabbing them like a hostage-taker, and snapping the photo for them.

Dude: Bro, do you dare me to go up to that girl and take a hostage selfie?
Other dude: Bro, that'd be awesome. She'll never expect it.

Girl: Bro, that guy is taking selfies. Dare me to run up behind him and take a hostage selfie with his phone?
Other girl: Bro, that'd be awesome. He'll never expect it.