World 8-3 is a level found in the game New Super Mario Bros..
The level starts above ground, and the player must jump into the pipe ahead. This will transport you underwater. Then you will start by swimming upwards, where small unagis try to eat you from their hiding places, and others swim by. Touching them will cause Mario to die if you're small, or cause you to lose your power up if you're not. Then you will reach the checkpoint right after a platform. Here there is an Item Box which contains a Mushroom if you're small, or a Fire Flower. Continuing to swim upwards, you will see a mega Unagi to your left, blocked by bricks. Then you must swim to your right as quickly as you can. Along the way there are Cheep Cheeps swimming, which you must avoid. There is also a few Stationary Unagis. This entire time, the Mega Unagi is trying to eat you and is destroying everything in front of it. There are a few pipes blowing jets of air, which you can use to put more distance between yourself and the Mega Unagi. however, these will usually be surrounded by a unagi or a Cheep Cheep. Once you reach the end of the level, there's a vertical green pipe which you swim into. This will lead you back above ground, and there will be some blocks you can jump on to get a higher jump on the flagpole.
- Star Coin 1: Slightly over halfway through the level; found on the floor.
- Star Coin 2: Almost immediately after the first Star Coin; found on the ceiling behind Brick Blocks.
- Star Coin 3: Towards the end of the underwater section; found above a pipe on the floor.