Oh, deer goodness.
This helmet is subclass neutral and allows for you to turn potentially disastrous situations into positive ones. This helmets exotic perk, Doe or Die allows your Super to charge faster when all your teammates are dead. It also allows for a chance to respawn with an overshield. As a result this exotic can allow you to survive for just a bit longer in the face of adversity. The helmet is overbearingly a PVE helmet as the faster Super charge when your fireteam is dead would be more useful in a Strike environment. It could serve some utility in 3v3 Crucible modes but with the other options for Warlock exotics out there, it is a mediocre choice.
Wearing the bones of a Stag is always fashionable in any circumstance and fighting the Darkness is no exception. The bleached white bones that comprise this helmet make you a force of fascination and a little bit of fear. On top of this the large horns sprouting from the top make sure that your Warlock is seen by every Guardian and enemy of the Darkness.
How to Acquire it?
The Stag can be gained from an exotic helmet engram or purchasing it from Xur if you are lucky enough for him to have it in his inventory.