Was at EGPF in the 80s when a USAF C5A arrived to pick up an American submarine to take home for servicing.
Doing walkround at LGW prior to flight to ESSA. Loaders were considering what to do about a box about 15'x3'x2' which was leaking clear fluid. Closer inspection revealed that it smelt of fish.Turned out that a Swedish holiday maker had caught a Marlin (?) whilst game fishing in the Seychelles and was shipping it back to Stockholm. I declined to take it, never did find out what happened to it.