Once Madcap Experiment begins resolving, no player may take any actions other than those specified by Madcap Experiment until it's done resolving.

Any abilities that trigger as the artifact enters the battlefield aren't put onto the stack until Madcap Experiment is done resolving.

The number of cards revealed this way includes the artifact card you put onto the battlefield.

If you don't reveal an artifact card, you'll randomize your library and be dealt damage equal to the number of cards in your library.