Läderlappen translates to "The Leather Patch" but it's also the name of a species of Bats.
This vinyl single is rare and I don't own it (yet..) but I found the song on a CD collection and laughed out loud because of the weird and funny lyrics. Here's a translation:
"Late at night when I go and fetch water,
I hear something that is very mysterious and scary.
So I scout around, this is a case I can solve.
I put on my tights, I go for it and fly....
Chorus:
Hidden behind the mask.
Batman is what they're calling me.
With my cape I can fly away.
Like a bat out of hell I go to every city.
There's no point in hiding away for me.
No villain can escape me."