Periwinkle is Pink's summoned nature spirit. It takes the form of a unicorn seemingly made of tree bark, but with an iridescent color reminiscent of moonlight. He earned his fame in Season 1 of Shadowrun. Blowback was waiting outside Pink's safehouse while Caber was meeting with Pink for the first time. Pink summoned Periwinkle to drive the "Corporate Oppressors" away. The only "Corporate Oppressor" above, was Blowback, who had simply come to check on Caber, as he could not reach him on comms. Periwinkle charged Blowback, who ran to the back of his van and dove in. Blowback landed on a jar of Pug's urine, that was stored in the van . When Caber returned, Blowback drove the van very aggressively to cause Caber to end up covered in the urine himself. Blowback succeeded. This event earned Periwinkle the nickname "Urinicorn".

Periwinkle is also the name of one of Diana Taylor's cats.