Blood-Nap is a unique variant of the Bowie knife that does bonus critical damage, gives a bonus critical chance, and adds +10 to Sneak.
This weapon qualifies as an improved holdout weapon.
It is possible to executeBlood-Nap outside of V.A.T.S. (without the required Melee skill of 50 to perform the move) by initiating a power attack (hold attack button) while moving forward.
Durability
Blood-Nap can successfully strike about 495 times from full condition before breaking.
Found in The Courier's Mile. This weapon becomes accessible only after first completing The Launch. It is found sticking out of a street lamp just to your left as you enter the area.
Notes
The weapon's Sneak bonus will be shown as "Activated" when the weapon is equipped, in an on-screen message.
It is one of the few unique weapons to date with the same appearance as its non-unique counterpart.
It may glow blue in dark areas.
The weapon itself may sometimes disappear during the sheathing animation.
Blood-Nap does more damage and has a higher DPS than even Chance's knife, making this an extremely formidable single-handed bladed weapon.
Blood-Nap's Sneak +10 does not act as a bonus, but rather as a raise in Sneak, i.e., if your character has it equipped when he/she levels up, some perks that require a higher Sneak (say your character has 50 Sneak but wants to get the Mister Sandman perk without spending the 10 points) will be available.
Behind the scenes
The name for the object effect associated with this weapon is "Dirt-Nap".