Spike Bass

The Spike Bass is an enemy in New Super Mario Bros. It resembles an oversized brown tadpole with a pale underbelly. It also has beaming yellow eyes, sharp teeth and spikes all over its body.

The Spike Bass appears in World 2-A and World 3-C. The Spike Bass jumps from the water and tries to attack Mario in a pattern extremely similar to a Boss Bass, but with no danger of being eaten. This enemy can be defeated with a Fireball, a Koopa Shell, a Starman or a Mega Mushroom. However, once defeated, another Spike Bass will return after a few seconds to continue the pursuit. Later games give this enemy's behavior to Porcupuffer, which formerly did not jump.

Reference
Stachel-Barsch