Maybe they are a fan of Whatchamacallits? If so this is the most terrible license plate evAR. BLEH!
Or maybe they were going for whachamahuh? The Urban Dictionary defines whachamahuh as:
1. I'm out of it don't mind me; 2. I am out of it, fill me in on what just happened; 3. I am out of it and almost beyond recovery; 4. I am beyond recovery don't even bother to fill me back in.
Yeah, I am beyond recovery right about now.