I have seen these on my floor several times now that spring has arrived and temps have started to go up. It is silvery in color, appears to have a hard and segmented shell, it kind of reminds me of a lobster. They are very small, the dark line in the picture is the grout between two tiles on my floor for scale. I am guessing it is about three quarters of a centimeter in length. I am in Utah.
This is a silverfish (Leipisma genus, the most common being Leipisma saccharinum). They are extremely common pests world-wide, eating a range of plant-based materials, particularly those made of cellulose - such as any pieces of paper you have lying around - books, book bindings/glues and cardboard. They will also eat things like cotton, silk, crumbs, dead insects (including other silverfish) and lots of other things too.
Unfortunately if you have seen one, you have many more around. Call a pest-control expert.