Armlet of Mordiggian

The Armlet of Mordiggian is an Item purchasable at the Main Shop, under Weapons.

Additional Information
Currently in DotA 2 heroes can buy multiple Armlets, but the active effect does not stack.

Armlet toggling
By turning on the armlet you will gain 475 hp due to the strength it gives you. You lose the health again when you deactivate it, but you cannot go below 1 hp. This can be used to your advantage. If you are below 475 hp, you will lose all your health except for 1. When you activate it again (quickly, so the enemy won't have time to kill you when you're at 1 hp) you will end up with 475 hp, more than what you had before. This can make you survive much longer. Remember that when you've toggled it twice there's a two second cooldown.

Trivia

 * Armlet of Mordiggian is named after Mordiggian in Lovecraft's Cthulu mythos, who would suck away life force and whose cult consisted of ghouls.
 * Armlet of Mordiggian health drain does affect Lone Druid's spirit bear, however, it does not gain any benefit from the 25 strength bonus when active.