WW2 german Buoy help needed!

[HxCMDP]

Hello all, i came across this piece, which was really appealing to me, because I never saw it before, it is a buoy, it wears markings, but they are no longer readable. does anybody has an idea what it was used for? It was said to be german, but i have found nohing to compare it too. all help is much appreciated. It measures over 1m on 70cm. When fully blown, i think it's quite a big one... greetings,


Matthias

[Danmark]

Looks like an oversize whoopee cushion to me

... not surprising because Adolf told some ripper fart jokes .....I read that somewhere!!