Potions of Grung, (Poisonous)

This concoction looks, smells, and tastes like dead
frog, to anyone other than a Grung (whom find it delicious). A non-grung whom drinks it could be poisoned and possibly die.
A Grung is affected as if they cast the
polymorph spell.
For one hour they may turn into a Frog (minor),
Giant Frog (major)