Forbidden Worlds #12 (American Comics Group, December 1952) is a six-feature pre-Code horror anthology under a Ken Bald cover, and it contains one of the strangest premises the series ever ran. "Were-Spider's Doom" introduces Mrs. Black, a half-human, half-spider hybrid preying on victims from her isolated home in the Smoky Mountains — until one of those victims turns out to be Mr. Vespid, a half-human, half-wasp hybrid, and the story becomes a monster-versus-monster duel drawn from actual entomology. Elsewhere, "The Chest of Death" releases a genie from an ancient box who sets out to keep a thousand-year-old promise to destroy humankind (with Abhen the Slayer, Kasmar, Akam and the Morrow family caught in it); "The Witch's Curse" sends honeymooners into the legacy the executed witches of Salem left behind, in a Jon Blummer-drawn story remembered by pre-Code fans for a spectacular animal transformation; and "True Ghost Armies" recounts the phantom army said to have appeared at the Battle of Buena Vista during the Mexican-American War. "The Haitian Puppet" and "The Tomb of the Unseen" complete a 36-page, full-colour, ten-cent package, with interior art by King Ward, Charles Nicholas and Jon L. Blummer under editor Richard E. Hughes, plus a letters page.

Forbidden Worlds launched in July/August 1951 as a dime comic subtitled "Exploring the Supernatural!", the companion to ACG's Adventures into the Unknown — the medium's first ongoing horror title. ACG was a small, resolutely independent New York publisher founded by Benjamin W. Sangor and co-owned by Fred Iger; the corporate name on the paperwork at this point was Preferred Publications, Inc. of Buffalo. Its horror line kept a house style distinct from the competition: atmospheric, often wry, and far lighter on gore and sexual content than the EC and Harvey books of the same year — one reason both ACG horror titles survived the 1954 Senate subcommittee hearings and the Comics Code without wholesale reinvention. Issue #12 closes the title's first full calendar year of monthly publication. The series ultimately ran 145 issues to August 1967 and won the 1964 Alley Award for Best Regularly Published Fantasy Comic.

What lifts issue #12 above routine is the collision of registers inside a single 36-page book: a Salem witch story played straight, a pseudo-documentary about ghost soldiers at Buena Vista, a Haitian voodoo tale, and then a monster fight between two insect hybrids that plays like a pulp-science fable. That range is exactly what pre-Code anthologies could do and post-Code ones could not. The letters page is worth a look too — ACG actively courted its readers (an earlier issue even printed a fan-written story), and the correspondence is a rare direct trace of who was actually buying these books in 1952. And because the material is generally treated as public domain in the United States, the original issue is freely readable through Comic Book Plus and the Digital Comic Museum.