Awkward silence
Awkward silence: an uncomfortable pause in conversation, causing tension or unpleasant feelings.
Example
Me: “I just found out today one of the guys at work had a prominent role in a TV show a few years ago.”
Family: “Really? What show?”
awkward silence
Richard
Classic! Uh, unless it's true. Then it'd just be awkward…
Dwight
Let's just say that was an actual conversation and response.