Earlier quoted context omitted.
It's actually true, in norwegian 'rumpetroll' means tadpole http://no.wikipedia.org/wiki/Rumpetroll but the literal translation is "ass troll", yes, seriously. that's why it's extra fun! especially if you are swedish like me ;)
I thought "rumpetroll" was a fake word along the lines of "guleböj" and "brusefåtölj" when I saw it. Fellow Swede here.
haha. yeah, when I first moved to Norway I couldn't believe it either :)