Sharks
From WikiRaider
You will meet Sharks in Tomb Raider II, The Golden Mask and Tomb Raider Underworld.
They will only be a danger to you, when in the water. You should try to get out of the water and shoot them from outside. If you cannot escape them, you should try using the Harpoon Gun against them. Their attacks are very dangerous and take big chunks out of your health.
Tomb Raider Underworld
In Tomb Raider Underworld Lara will use her Pistols to kill the sharks and she has a Harpoon Gun as well in this game. They will appear in the Mediterranean Sea and Thailand, also using a Sticky Grenade to kill them easily.