@Otteresting Just as @The Grym Reaper had said, mealworms and some of their close relatives (darkling beetles) are used by many people as clean up crew in cricket and roach colonies since they are voracious and will eat almost anything. Dead roaches, roach waste, and leftover food particles are all fair game for these little guys. However, larger species like superworms (Zophobas morio) are not commonly used due to them often being more aggressive and more likely to eat the live roaches or crickets.
I would guess it is a newborn mealworm. If anything it will benefit your roach colony. They are also great for feeding tiny slings and other small critters when they are this size if you'd rather not risk it.