Other mistake: Irv and Blaire's death scene doesn't make sense. When Irv poured butter on the popcorn, he should've noticed the spider in the bowl. Also, when Blaire picked the spider up, she should've felt it. Both of them still appeared to be watching the TV after being bitten, which also didn't make sense. Why didn't they have seizures like the other victims?
Other mistake: The wood coffin that Jerry Manley is placed in has no bottom. Right after showing him in the coffin they seal the top, insert handles and somehow carry him off.
Answer: The small spiders are Avondale spiders from New Zealand. They are totally harmless to humans.
Hamster