contrabass flute
Basically, a giant flute. It's like a contrabass saxophone or a contrabass clarinet, but it's a flute.
Person 1: "Woah! That's a giant flute! Is it an alto flute, or a bass flute?"
Person 2: "Neither. It's a contrabass flute!"
Person 2: "Neither. It's a contrabass flute!"