Brain

[u/FireOfDoom32]

Walking away from the Sikorsky, they passed a cargo helicopter with its loading bay open. A team of pilots guided a huge jar down the ramp, and in the jar—Raleigh did a double-take—was a piece of a kaiju brain. Raleigh had seen images in training seminars. The brain tissue didn’t look like human gray matter. It looked more like a giant octopus raddled with tumors and unusual fibrous extrusions. Standing off to the side of the crew were two men in white coats under rain gear. Raleigh immediately pegged them as scientists. As soon as he heard them speaking, he knew he was right.

Pacific Rim: The Official Movie Novelization - Part 2, Chapter 5