Squid and their cephalopod brethren have been the inspiration for many a science fiction creature. Their slippery appendages, huge proportions, and inking abilities can be downright shudder-inducing. (See: Arrival.) But you should probably be more concerned by the cephalopod's huge brain—which not only helps it solve tricky puzzles, but also lets it converse in its own sign language.

Right now, you're probably imagining twisted tentacles spelling out creepy cephalopod communiqués. But it's not that: Certain kinds of squid send messages by manipulating the color of their skin. "Their body patterning is fantastic, fabulous," says Chuan-Chin Chiao, a neuroscientist at National Tsing Hua University in Taiwan. They can display bands, or stripes, or turn completely dark or light. And Chiao is trying to crack their code.

Chiao got his inspiration from physiologist B. B. Boycott, who in the 1960s showed that the cuttlefish brain was the control center for changing skin color. Boycott copied his technique from neurosurgeon Wilder Penfield, who treated epilepsy patients by burning out the misbehaving bits of their brains. While their grey matter was exposed for surgery, Penfield also applied a gentle current through the electrodes in his patients' brains. You know, just to see what would happen.