On the Edge of Forever

When Dr. Strange cast a cloaking spell to disguise both himself and Sub-Mariner as ordinary people in Defenders #4 (Volume 3), he took wardrobe advice from Star Trek. The spell logically dressed Sub-Mariner in a stocking cap to cover his pointed ears, much like the hat Mr. Spock wore in The City of the Edge of Forever to cover his similarly pointed ears. Dr. Strange, meanwhile, wore a red, flannel shirt reminiscent of the shirt Capt. Kirk wore that same episode.

Note the reverse symmetry regarding the other color choices: While Kirk's jacket was brown and Spock's hat was blue, Sub-Mariner wore a brown hat and Dr Strange had a blue jacket.