What plant produces this seed pod?
This appears to be a Jack-in-the-pulpit (Arisaema triphyllum) berry cluster. The spadix or "Jack" produces tiny flowers in the spring that are pollinated by flies. Pollinated flowers produce green berries that turn bright red in late summer and fall. Seeds within the berries that fall to the ground will germinate the following spring producing one small leaf. Jack-in-the-pulpits need three or more years to mature before they flower. The plants and fruits contain calcium oxalate that may irritate your skin so it is best to wear gloves when handling them. I have attached two images of the plant.