A booger-like lump found in your hair which appears as the result of applying too much hair product, or not spreading the product out properly. It looks suspiciously like a booger which leads to you having to explain the product mishap to those who point it out, so they don't assume it is a real booger in your hair.
Cam: What's that in your hair? Looks like a big booger... (reaches out to pick out out but recoils as he thinks it is a booger)
Jake: Crap... it's a hair booger, too much fudge on the hair this morning...
Cam: Yeah riiiiiight.... more like you picked a winner and scratched your head after....
A booger found in the hair; typically found on the heads of elementary age individuals, although there are rare, greasy exceptions to this rule.
Little Christopher: (picks nose and wipes it into hair while sitting in his 3rd grade classroom)
Little Sally: EWWW CHRISTOPHER HAS A HAIR BOOGER!
Little Christopher: (begins crying and picks boogers out of hair and eats them)
Big Christopher: (Sitting at his construction sight, he picks a winner and stashes it in his hair)
Big Sally: (Walks by after years of not seeing him) EW! CHRISTOPHER HAS A HAIR BOOGER!
Everyone on the street: EWWWWWWWWW!
Big Christopher: (begins crying and picks boogers out of hair and eats them)