Definitely spiders. You never specified what type. I'd choose some harmless type--tarantulas can be tamed and can actually be rather friendly and pleasant to hold. Maggots on the other hand are pure destruction O.O
F-uck spiders. I would definitely pick maggots. Even if the spiders are harmless I would still probably hurt myself trying to get away.
Maggot only eat dead cells so it would be like extreme exfoliation or something. Spiders bite.
Bills. Definitely bills.
Probably maggots, they can't really hurt you. Well, most cant.