In early 1971 cartoonist Dan O'Neill invited Hallgren — then based in Seattle — and some other artists to San Francisco to form the Air Pirates collective.[2] The Air Pirates lived together in a warehouse on Harrison Street in San Francisco.[3] They teamed up to produce two issues of Air Pirates Funnies. Hallgren's work in Air Pirates Funnies, Pollyanna Pals, imitated Cliff Sterrett's old-time comic stripPolly and Her Pals.[2]Air Pirates Funnies contained parody versions of (among other figures) Mickey Mouse, which led to a highly publicized lawsuit from The Walt Disney Company.[4] Hallgren also did the cover artwork and stories for a follow-up comic, The Tortoise and the Hare (Last Gasp, 1971) (of which nearly 10,000 issues were soon confiscated under a court order).[5] The initial court decision, delivered on July 7, 1972, went against the Air Pirates, and O'Neill's lawyers appealed to the United States Court of Appeals for the Ninth Circuit. O'Neill suggested the other Pirates settle, and leave him to defend the case alone. Hallgren and the publisher, Ron Turner, settled with Disney.
Hallgren illustrated Mehmet Oz's book, YOU: The Owner’s Manual: An Insider’s Guide to the Body That Will Make You Healthier and Younger, published in May 2005 by William Morrow Paperbacks.
^Cooke, Jon B. (October 2000). "Simonson Says The Man of Two Gods Recalls His 25+ Years in Comics". Comic Book Artist (10). Raleigh, North Carolina: TwoMorrows Publishing: 25.
^ abCadigan, Glen. James Sherman interview, The Legion Companion (TwoMorrows Publishing, 2003), p. 113.
^I ALMOST DREW NANCY, by Ivan Brunetti; in Roctober magazine, #26 (1999/2000); archived online at MikeLynchCartoons.blogspot.com; retrieved October 25, 2016