Acidquill is a breed of Category III Kaiju.
Acidquill is a bipedal Kaiju with seven limbs: two arms, two legs, two tendrils and a tail. The Kaiju's arms are significantly larger and stronger than its legs, and it primarily uses them to support itself, striding on its knuckles. Its legs are still used in combat, but normally hang idle. Acidquill has two tendrils extending from its back which can pierce the armor of a Jaeger. Its tail is also used in combat and for balance.
During Striker Berserker's defense of a PPDC building, Acidquill kills Herc Hanson's a co-pilot, leaving him to fight on his own. Following a grueling fight, Striker Berserker impales Acidquill through the chin, and its dead weight topples the Jaeger.
In Meridian City, following the execution of Operation Blackout, another Acidquill ambushes Hunter Vertigo during its attempts to transport civilians to safety. It's shot down by Marauder Zeus. Immediately after this, another Acidquill arbutuses Marauder Zeus, stabbing it from behind. The Jaeger fires on the Kaiju until it leaps onto its shoulders and attacks its Conn-Pod, which triggers an explosion that kills both pilots.
During Hunter Vertigo’s journey to Shadow Basin, either the same or another Acidquill pursued and attacked the Jaeger and Meridian City's refugees. It’s able to damage one of Hunter Vertigo’s Cryo Cannons, before the Jaeger uses the nuclear missile the Kaiju deflected earlier to kill it.
Acidquill bests the disadvantaged Atlas Destroyer during their fight, evading its single arm attacks with ease. Leaping onto the Jaeger, it intends to pierce the Jaeger’s armor with its claws, but is pulled off by the Kaiju-Jaeger Hybrid, Apex. Apex grabs Acidquill from behind and tail and smashes it into a rock. Smashing it into the ground, Apex leaps on Acidquill, and stabs the Kaiju in the head.
- Acidquill, and the remains of Leatherback, Mutavore, and Slattern in the Boneyard, reinforces Newton Geiszler's assertion that the Kaiju are clones.[note 1]
- Newton Geiszler: "Now this one here was harvested in Sydney. And this was harvested in Manila, six years ago. They have the same exact DNA. They’re clones."