The act of lurking just outside the bathroom door when another person is using it, usually accompanied by some attention-seeking noise or behavior, ensuring that that person will acknowledge your presence and hurry up.

A Tankietank is a rare species of Shower Goblin that enters your bathroom through the toilet. You cannot prepare for this intrusion as you may be in the shower, brushing your teeth or simply in the room next door. You never know when he is going to bubble his way up to the surface. If you suspect you have a Tankietank stalking you look out for the signs of puddles the size of flippers in the places that you have recently been. If you encounter this creature it will most likely be wearing a Snorkel, Flippers, Goggles and have a Mixmaster on its back.

DO NOT: Make any sudden movements.
DO NOT: Attempt to get him back in the toilet - This will anger the creature and provoke an attack.