BRANDON "Greasy Bear" Davis, grandson of the late oil billionaire Marvin Davis, has worn out his welcome as a house guest of one of his few friends, music producer Scott Storch. The other night, "Brandon and Scott went out and Brandon went back to Scott's place and crashed on the couch," a source said. "The next morning, when Scott got up, Brandon was already gone — and so was Scott's $100,000 diamond encrusted watch that had been in the same room the night before. Scott called Brandon and told him the watch was missing but, 'It's OK — I just got a new security system, so everything's on tape.' " After learning he'd be caught, Davis "started crying hysterically and saying, 'Please don't tell anyone — I'll bring it back.' Scott felt bad for him and got his watch back like an hour later, so he didn't call the police."