Moose Matson, played by William B. Davidson, is a character in the 1941 film Hold That Ghost.
Matson is a rich gangster who is wanted by the police. While stopping for gas, the police notice him and give chase. Unfortunately for the two gas station attendants Ferdie Jones and Chuck Murray, they were trapped in the vehicle and went along for the ride.
Not long after the chase began, Moose was shot and killed. He never trusted any of his associates, so he left his estate to whoever was closest to him when he died, which happened to be Ferdie and Chuck.
His cryptic message about "always keeping his money in his head" led to Ferdie discovering thousands or even millions of dollars stuffed in a taxidermied moose head.