Sharks?
Lasers?
Laser sharks?

Why not all three, with Sharks with Lasers!

Create a laser collar and put it on your not-so-friendly water puppies so they may randomly shoot things they are looking at! Its so evil it brings a tear to my eye. An evil tear of course.

If you have the resources to spare, you might even be able to create a robotic version that is stronger, tougher, and can even swim in lava! (and can also wear a laser collar of course)

Crafting recipes:

Iron Wire:

Iron Mesh:

Sifter:

Use Sifter:

Cook Silicate Dust into Silicon:

Microchip:

Cook Glass into Forged Glass:

Focus Lenses:

Laser Module:

Laser Collar:

Redstone Core:

Redstone Singularity:

Robot Core:

Motherboard:

Wiring:

Robot Eye:

Robot Shark Parts:

The robot shark requires a large amount of resources, specifically:

87 Redstone Dust
74 Iron Ingots
33 Sand
7 Copper Ingots
2 Iron Nuggets
8 Shark Teeth
5 Shark Fins

Iron shark parts must first be made such as

Iron Shark Fin:

Iron Shark Jaw:

Robot Shark Brain:

After the base pieces are made, you can put them together into the pieces of the robot

Robot Shark Head:

Robot Shark Chassis:

Robot Shark Tail:

The pieces must be placed in the world attatched to each other:

Once the pieces are assembled, using a Robot Core on any piece creates a bran new robot!

Planned Additions:

Laser alarm
Laser gun
Vat of acid
Piranhas (+ robot version)
Redstone countdowns
Monocle