A money crab is a person who loves money and is very stingy. The crab in the detention is reference to Mr Krabs from Spongebob who has the same characteristics as a crab Jew. Crab jews love to wrap their claws around some change they found on the ground.
Dylan was called a Money Crab when he started charginginterest on the $.50 he loaned to a friend.
Supplemental Security Income (SSI), Social Security Disability or any other type of disability payment given to someone who is considered unemployable due to mental or behavioral health reasons.