SLW3

Someone who lacks basic critical thinking, almost to the point that you're surprised that they have motor functions.

A typical SLW3 is very airheaded and unaware of their surroundings, and are typically regarded as a very stupid person
An SLW3 may also be recognised as a species incapable of operating anything with an engine inside it, whether it's a car, plane or boat.

Person 1: "Wow, did you see that crash on the highway? Everyone involved ended up dying!"
Person 2: "Really? The driver that caused it must've been really bad... Must've been a SLW3"