A Midsummer Night's Dream 3.1 Interview: Puck

The video features an interview with Robin Goodfellow, also known as Puck, who is on a mission in the woods to find a wild beast for Titania. He encounters Athenian workers rehearsing a play and decides to stick around, eventually devising a mischievous plan involving the actors. The video concludes with Puck hinting at his plan and bidding farewell.

What idea does Robin Goodfellow get while watching the Athenian workers?

What does Robin Goodfellow imply will happen when he gets an idea?