Honestly hadd to say. Looks to me like an arthropod, and perhaps even an insect. Just maybe those extra legs are pseuodopods (like the fake legs of a caterpillar) of a nymph (juvenile). It could be a dragonfly larva? There is no indication of size, but seems like baby dragonfly that I have seen in the past. If small though, it could be a silverfish. Those aren’t insects, just arthropods, they are related to slaters.