Flying
When this creature enters, mill three cards. (Put the top three cards of your library into your graveyard.)
Threshold — This creature gets +2/+1 as long as there are seven or more cards in your graveyard.
Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to Billowing Shriekmass may become lethal if the number of cards in your graveyard falls below seven.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.