Have a room with a glass floor that has water underneath it, fill it with squids, cause I guess without mo' creatures, that's the closest to a shark you can get.
Needs more:
Corridors with flickering lights
Noteblock turtle playing toccata and fugue in D minor in a loop
Lava curtain door
Long hall with turrets behind retractable glass, preferably with a pool of liquid ender suspended above the hall with glass that's likewise retractable
Random high energy pellet launchers
Cow launchers
Have an infintite loop of golems transporting uranium/tnt/buckets of lava arround your base, maybe under a glass floor?