300000 cp??

Probably another Glitch related to the Testing of Legendary raids. That is my best guess.

It's a MissingNo Raid Boss!
It will multiply the first item in your bag to 99x, so make sure you have Charged TMs as first before you start the battle!

That's just the standard coding errors for an empty gym in error. It's not very unusual to see this glitch.

It's the new SOLO challenge. Time limit, 12 minutes. Throw the kitchen sink at it!

It's a little like this screen I got stuck in yesterday after failing a Lapras raid.