There is a cage on the left side of the screen, and an octopus-like alien walking toward it from the right. The player must press the button with good timing to drop the bars on the cage and trap the alien. The player may drop the bars on the alien as well. Depending on where they hit the alien, it will either be pushed inside or pushed out.
1st level difficulty: The alien walks straight through.
2nd level difficulty: The alien pauses or jumps before walking through.
3rd level difficulty: The alien pauses shortly, then curls into a ball and rolls through the cage at twice its normal speed.
