Underwater Spikes
From WikiRaider
Underwater Spikes in The Vault of Trophies
The Underwater Spikes are traps found in Tomb Raider VI in The Vault of Trophies and Eckhardt's Lab.
These retracting spikes can be found only underwater. If Lara swims near a certain part of the wall, several spikes will pop out and injure her.