Vindictive Vampire

• WWizards of the Coast2019-01-25
  Official Ruling
  If your life total is brought to 0 or less at the same time that creatures you control are dealt lethal damage, you lose the game before Vindictive Vampire’s triggered ability goes on the stack.
• WWizards of the Coast2019-01-25
  Official Ruling
  In a Two-Headed Giant game, Vindictive Vampire’s ability causes the opposing team to lose 2 life and you gain 1 life.
• WWizards of the Coast2019-01-25
  Official Ruling
  If Vindictive Vampire dies at the same time as one or more other creatures you control, Vindictive Vampire’s ability triggers for each of those other creatures.

Rulings via Scryfall