When an elementary school student is labeled the "class clown" by his teacher and then adopts the persona and lives up to others' expectations by acting silly, the class clown label has become a: ?

The class clown label has become a stigma. A stigma could be described as a symbol in which it is labeled because of circumstances in which  a person or thing is described such as the class clown is labeled as a stigma because of his funny and silly character.

cannabis

explanation:

(assuming this is the us) google it. law states you can't have weed.

the atm that sounds like it should be the answer