I just got a Radio Mushroom e-QSL, less than 24 hours from the broadcast. It was actually sent only 11 hours after my reception report e-mail.
The e-mail had this text with it:
"Hello Zack;
Sorry for creating such as mess again, but whenever we power our transmitter with pure nuclear energy we always seem to create a mushroom cloud.
We were directly tapped into the core of a nuclear reactor last night which powered the broadcast you heard last night. Thank you for listening and letting us know Radio Mushroom was heard.
Attached is our newest QSL confirmation card. Handle it with care as it is probably a bit radioactive.
Radio Mushroom"
If I can figure out how to post a picture, I'll post the QSL too.
Thanks again Radio Mushroom!