A Clumsy person.
That kid drops everything all the time, he's such a klutz
A person who is never without a scrape or bruise. Always finds a way to trip, bump into things and people. And on occasion, they partially knock themselves out by walking into walls, doorways, and corners or cabinets and desks.
Why didn't I see that corner of the desk? I'm such a klutz! Where's the frozen corn?