"Hi there fellow. Yep, I'm trapped in this cage, wanna let me out? No you don't, my name is Genie, or is it satan? Maybe Dracula? they have all been imprisoned in boxes every so often but not for long. Better not let me out, get away from that latch!"
Then if some smart ass touches the latch , have a hidden switch inside the cage that temporarilly interupts the room's lighting, going to full darkness for a second or two.