Hunter's Grenade

The Hunter's Grenade is a single-use Grenade skill. Unlike most skills, the Hunter's Grenade deals no damage, nor does it affect the player. Instead, it only affects enemies that drop uncollected blueprints, turning them into a challenge for a guaranteed blueprint drop.

Throwing the Hunter's Grenade at an eligible enemy will power them up into an Elite version, drops a Blueprint Extractor nearby, and then the grenade will disappear.

If all blueprints from the enemy type have already been acquired, the enemy is a boss, or the grenade misses, the Hunter's Grenade will drop harmlessly to the ground, allowing the player to pick it up again.

Enemies hit by the Hunter's Grenade that have no Elite variant (for example, flying enemies like Buzzcutters and Kamizakes or static enemies like the Protector) will instead transform into a standard Elite Zombie. The extracted blueprint will still be from that enemy's loot pool, however.

The Hunter's Grenade is unlocked from the Collector through the Specialist's Showroom upgrade. Once unlocked, it always appears in The Prisoners' Quarters behind a gold door within the Specialist's Shop, which can be unlocked for 7500 gold, or destroyed for a 50-kill curse.

Blueprint Extractor
The Blueprint Extractor is a skill produced when the Hunter's Grenade successfully activates. It is only usable on the targeted Elite enemy when its health is below 40%. Activating the Blueprint Extractor in range of the enemy roots the player in place and channels a beam for 1.3 seconds. If the channeling succeeds, it kills the enemy and forces one of its blueprints to drop, then the Blueprint Extractor disappears.

A message appears onscreen when the enemy drops below 40% health, so wait to use the Extractor until you see it. Taking damage interrupts the channeling, so it is recommended to use skills that stun, freeze, or slow down enemies, or make the player invincible.

If the enemy dies before the Blueprint Extractor is used, both will disappear but another Hunter's Grenade will drop, allowing the player to use it again.