jack-a-leg
A clueless mess who can't do anything right. They're like a confused turtle who can't find its way home.
My neighbor is a jack-a-leg, he tried to fix my sink and now it leaks everywhere.
My math teacher called me a jack-a-leg because I couldn't solve the problem.
That kid is a jack-a-leg, he drew a cat on the blackboard and then cried when it got erased.