You know the deal. Big Bird is just standing there, and he opens a door. It is the perfect green screen template for when you want to react to something absolutely wild. Someone drops a hot take in the group chat? Big Bird opens the door. Your boss sends a confusing email? Big Bird opens the door.
It works for any meme reaction where you need that specific feeling of "I just walked in on something I wasn't supposed to see." Drop any chaotic background behind him. The juxtaposition is what makes it funny. This template is pure meme gold for any editor looking for a quick laugh.