Shark

The Shark is an enemy that is found in the oceans on either side of the world. They have 300 health and can do decent damage, which makes the oceans a dangerous place. Sharks only spawn within 250 blocks from the edges of the map and will not spawn anywhere else.

Strategy
Sharks charge directly at the player and can move quicker than you. They are resistant to knock-back, but weapons unable to knock them back will usually stop them advancing; rapid weapons are therefore useful against sharks, and the Aqua Scepter is particularly useful. Spiky Balls, when thrown while on the bottom of the ocean, are also very effective against sharks, as they ram themselves through them, taking all three hits quickly.

Alternatively, just using a Flail or Boomerang from outside the water can quickly bring them down. The locally available Trident is highly effective at bringing down sharks, as it will always hit 3 times when passing through the shark.

Yet another method of farming/defending is to dig a spot for player to stand on but still be inside water (but not drowning), then to add a shield of blocks in front of this standing section to one tile above the water's "level". A similar method is to stay in the water, create an arc shaped section of blocks, destroy the part connected to the ground, and stand to the left of it. Sharks will then go under it and try to attack you, but they won't fit. From there you will be able to attack them with your weapons. Additionally, playing random notes with a Bell while standing in the water will increase the chance of Sharks spawning. Sharks (and other ocean creatures) will keep charging at player due to a bug with all bodies of water being treated the same for AI. The player can then use a ranged weapon (like ones listed above) or use weapons such as the Flamelash or Magic Missile or even bows or Grenades over the barrier.

History
Requin Shark Shark Акула