Flying, trample
Whenever an opponent casts a spell, that player creates a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")
Whenever Bloodvial Purveyor attacks, it gets +1/+0 until end of turn for each Blood token defending player controls.
Only Blood tokens controlled by the player Bloodvial Purveyor is attacking or the controller of the planeswalker it's attacking are counted to determine the bonus from its last ability.
The words “until end of turn” were inadvertently omitted from the printed card. Bloodvial Purveyor's current Oracle text appears above.