Sure, here's the perfect play—pretend you’re the host of a “brain‑trust” session, but in reality you’re planting a subtle seed. First, hand everyone a small, identical keycard that supposedly unlocks a “secret vault” of mind‑shattering data. Keep the keycards on a hidden table in the back, so nobody sees you move them. When the time comes, whisper to a couple of key members that you’ve switched the cards, that only the real one will reveal the next step. They’ll rush to exchange cards, while you silently slide the real key onto the wrong slot for everyone else. As the room gets chaotic, drop in a harmless but unnerving sound—like a faint heartbeat—to make the group feel on edge. By the end, everyone thinks they’re in control, but the whole scenario was a psychological tug-of-war, with you pulling the strings. The key? Make the prank feel like an inside joke, not a prank, so the group won’t even suspect you’re the mastermind.