I don't know what a tulip vase is - specifically for tulips presumably - but what might it be about toolips that would require a frog like this - the leaves maybe?
It's an insert by the looks of the open bottom, and assuming that's correct, then its size would suggest a substantial vase in which to locate this frog. Might be worth checking the vases on Pamela's pressed 'glass pavillon' - if you've not already done so.
Otherwise I'm clueless - sorry - but very interesting and unusual.