The Fermi Paradox got them

A phrase used to describe when someone you know ghosts you or disappears from your life.

It can also be used when someone stops talking to you mid-conversation and vanishes for long periods of time without an explanation given to you before or after.

The joke is that they were met with an extinction event that they couldn't survive through and now do not exist.

Thespy: Shit, where the fuck did Nick go?
Caribou: I have no idea, The Fermi Paradox got them.
Thespy: The extinction event is real.