The Junkers Ju-390 (based on the 4-engine Ju-290) was a massive 6-engine long-range bomber.  Lucky for us, the war ended before it went into production.  The bomber here might be one of the prototypes–sharing the fuselage shape of the two 390 prototypes that we know of, but with the 4 engines of its predecessor.  Regardless, our American soldiers would never have seen anything like it before.