Should I stay or should I go?

During a Modern PPTQ, Andy casts Collected Company. As it resolves, he puts Murderous Redcap and Kitchen Finks onto the battlefield and says “Two to your face.” He then puts the other four cards on the bottom of his library. Nolan grabs his pen, and at that point Andy realizes his mistake. “I couldn’t have chosen the Redcap. He costs four. Judge!”

What do you do?

Judges, feel free to discuss this scenario on Judge Apps!

Answer
Nathen Millbank nails it square on the head with his analysis. This is indeed a Game Rule Violation for Andy, he resolved a spell wrong, and a Failure to Maintain Game State for Nolan, he had plenty of time to catch the mistake, after all, he let the spell resolve and acknowledged the trigger that resulted from the creature entering the battlefield.

Quite a few people suggested downgrading the penalty here since Andy called the judge on himself before benefiting from it, but there is an additional condition for a downgrade to be possible: “…calls a judge over immediately (as the infraction happens)…” which is not the case here. Even the fact he did not benefit from it is only half true as he now knows his opponent has no response to two damage from a Redcap entering the battlefield.

Now for the fix: There are no partial fixes that apply in this case, so all we are left with is to leave the situation as is or rewind. The latter is pretty easy here, rewinding to the resolution of the Collected Company means taking the Redcap and Finks, the bottom 4 cards of the library and putting them back on top of the library. Collected company is resolving.