Update: spoke to mojos vet. He said to watch his behavior as you mentioned in above post. Since the lego piece was so small he should be able to pass it. If i notice any of the above symptoms, take him in. Thank you!
I left my room for about five minutes, to find my kitten had gotten into my roommates room and was chewing on this small string that (used to) have a small lego part connected to it. It is about the size of a popcorn kernel. I am almost certain kitty ate it since i pulled the string from his...