Did he bring instructions for you to begin your quest?

Paint him one of orange, blue, purple, or red. Name based on color. If more turtles show up, repeat process. Then once you’ve done this four times, you’ll hence forth be known as Splinter.

He's adorable 😍

Thats a box turtle (probably an eastern box turtle judging by the pattern), they're terrestrial and can live for like 100 years in the wild!