- "Thrown ballistic that explodes on enemy impact. Can be recovered after use."
- — In-game description
It retains the crosshairs and the sound effects of the Throwing Knife, as they are very similar equipment, with the main difference being that Bio Spike explodes upon impact of an enemy body.
In multiplayer, the Bio Spike is unlocked as lethal equipment at level 50. It deals the same damage as a regular Knife, it's explosive impact radius is small, but the explosion will always result in a kill if caught in that radius.
Players will receive only one spike; however, any thrown spike can be retrieved, regardless of who threw it, assuming the player has selected the Bio Spike as equipment. It can also be replenished with Warfighter's Resupply trait.
After throwing the spike, a number of events can happen:
- The spike hits an enemy player, scoring a kill with the explosive aftermath potentially killing teammates and/or the thrower.
- The spike hits a friendly player, dealing no damage but leaving the spike embedded in the body, unless on Hardcore game modes, where the damage will be dealt back to the thrower or cause a Team Kill.
- The spike hits the ground at a certain angle, causing it to clatter to a stop, where it can be retrieved.
- The spike becomes embedded in a surface (walls, etc.) from where it can be retrieved.
- The spike hits any surface at a certain angle, causing it to ricochet (as with the Grenade Launcher) and flip several extra feet. In this instance, the spike is still deadly and can kill, provided it does not stop moving.
The Bio Spike is popular with stealth classes as it is silent, gives no warning (unlike grenades), and even if the player misses, there is a good chance the target will not notice (unless they see the spike go straight by or they hear it ricochet).
However, it has a short effective range, as it rapidly descends towards the ground the farther it is thrown. Thus, at longer ranges it is necessary to aim above the target for it to be thrown accurately. The Bio Spike is considered one of the hardest weapons to master because it requires practice to aim at targets and throw it, usually in a quick succession and during movement.
The Bio Spike is available on all Zombies maps and can be attained by picking them up from backpacks dropped by killed zombies.