Apart from Chris's wonderful suggestion of ,,Zankapfel'', my humble suggestion would be ,,Donnerplumps'', which more or less translates to 'Thunderplop', and I'm being told 'torden plask' in Danish, which is more like thunder-splash.
I really wanted to call it 'Thunder Bubble' which is great in English and Danish, but not so much fun in German. Stupid ,,Donner Blase''.
Anything with Knoedeln in is good though. Sorry, can't do umlauts on this forum, I never learned how.