This is the last thing i made at uni. Its a broach and it was based on a puffer fish! the black spherical ball was hollow and cut in half then the top half cut into quarters. On the inside edge of each quarter, i set magnetic strips to hold them shut. Inside the ball was large red balloon attached to a valve built into the broach back. out of the back of the broach came a clear tube which had a pressurized air canister on the other end, which could be clipped to the back out of sight. at the press of a button it went from a small unassuming ball to a large red balloon which if fully inflated could reach the size of the model.
modeled by Chris