Many get freaked out by snakes. Fortunately IMO we don't have snake issues in Michigan. In my school days I would freak out if a snake was roaming around the classroom.
A snake in a Kentucky sixth grade classroom escaped its terrarium. Teacher Max Haupt commented, "I think I just didn't put the lid on secure enough." After not discovering the snake for tree months, "Thirsty yet unharmed, Gummy Worm has been safely returned to her terrarium." More here.