Hunter's Grenade

Hunter's Grenade is a single-use skill. Unlike most other skills, the Hunter's Grenade deals no damage, nor does it affect the player. Instead, it only affects enemies with blueprints that you have not collected, turning the affected enemy into an elite version, dropping a Blueprint Extractor nearby, and disappearing. If a) all blueprints from the enemy type have already been acquired, b) the enemy has no elite version (e.g. immobile and flying enemies), or c) no enemies are hit, the Hunter's Grenade will fail to apply its effects, allowing the player to pick it up for another throw.

This item is unlocked from the Collector for 100 cells and, once unlocked, always appears in The Prisoners' Cells 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 which is only usable on the target elite enemy while its health is below 40%. Activating the skill within range of the enemy roots the player in place and channels a beam for 1.3 seconds, killing the enemy (?) and forcing one of its blueprints to drop before disappearing. Taking damage during the channel interrupts the process, so it is recommended to employ some means of gaining invincibility or preventing enemies from acting in order to ensure that the extraction process can be completed.