facebook double-take
Person A acts like they're a detective because they know Person B was somewhere or did something. Person B is confused and starts sweating. Then Person A drops the bomb and says they saw it on Facebook.
'You were at the store? Why? I didn’t tell you!' 'I saw your post on Facebook, you fraud!'
'You got a new dog? Why? I didn’t say anything!' 'I saw your Facebook, you liar!'
'You ate my pizza? Why? I didn’t tell you!' 'I saw your Facebook post, you cheater!'