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 or immobile enemies like the Protector) will instead transform into a standard Elite Zombie that can have the original enemy's blueprint extracted.

The Hunter's Grenade is unlocked from the Collector for 150 cells. Once unlocked, it always appears in The Prisoners' Quarters behind a gold door which can be unlocked for 7500 gold, or destroyed for a 30-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, then the Extractor vanishes, the Hunter's Grenade is wasted, and the enemy drops nothing.

Trivia
The Hunter's Grenade can be seen as a reference to the Poke Ball, a spherical device used to capture Pokémon in the well-known Pokémon franchise:
 * The description of the item is a reference to the franchise's "Gotta catch'em all!" slogan.
 * In early development for the Baguette Update, the Hunter's Grenade was instead named "Pokebomb".
 * When the Grenade-spawned Elite is below 40% health, an icon that looks like a Poke Ball appears over them
 * The fact that the Elite must be weakened before using the Blueprint Extractor might be a reference to the capture mechanic in the video games, where the chances of capturing a Pokémon increase as their health decreases.