This was the hat Hornaday wore when he worked at the Bronx zoo and conducted his infamous experiment in 1906 to demonstrate the missing link by putting a human pygmy in a cage with chimpanzees. When the artifact is thrown near the target(s), they become wrapped in a silk cocoon that attaches itself to the nearest surface. Used by the Mrs. Frederic created in Artie's subconscious to prevent Steve and Claudia from waking Artie up.
Claudia and Steve cocooned