Moved from ID Request.

There is a species that is introduced in Hawaii that has blue legs: Scolopendra subspinipes. The blue turns to red as they age, apparently, so it may be a juvenile of the same species as your larger outdoor critters. You'll want to check with someone more local or more knowledgable, though, or see if you can get a better photo. If that is what you have, it may make you feel better to know that people keep them as pets, but yes, they bite, and some people do have an allergic reaction to the bite, so they are the kind of pet that usually lives in a pretty aquarium and isn't actually petted. Not dangerous like a poisonous snake. More like a bee sting, from what I understand. These eat other insects, so if you're finding them in your house occasionally, they probably just wandered in from outside and you can shoo them back out again. If you find them all the time that would indicate you've got a larger pest problem that they are actually helping control for you.