Whispy Sour

You gain a flying speed of 10 feet for 1
minute, but can only hover 1 foot above the ground when doing so.
For 1 minute after drinking this potion, you
can regain 1d8 + 2 hit points once on each of
your turns when you reduce a hostile creature to 0 hit points. If the creature is a construct or undead, you don't regain any
hit points in this way.