karma shark
A portmanteau on the words “karma” and “business shark”; a karma shark is a selfish person who superficially does selfless things such as charity, favors, etc. expecting rewards. Such a person believes good deeds or good karma should be treated as credit in order to gain materialistic rewards. A karma shark will often try to manipulate, guilt trip, emotionally blackmail, or peer pressure people into doing favors in return for said acts of generosity loaded with selfishness.
That dude was such a sleazy karma shark for doing all those favors with strings attached!