The amount of life you lose is determined by the mana value of the card in your graveyard, not the creature once it's on the battlefield.
07-12-2018
wotc
You lose life after the creature is already on the battlefield. Any abilities it has that interact with loss of life, such as that of Platinum Emperion, apply to that loss of life.
07-12-2018
wotc
In a multiplayer game, if a player leaves the game, all cards that player owns leave as well. If you leave the game, the creature you control from Reanimate is exiled.
07-12-2018
wotc
If any abilities trigger on the creature entering the battlefield, those abilities resolve after you lose life. If losing life results in you losing the game, those abilities won't resolve.
07-12-2018
wotc
If a card in a player's graveyard has {X} in its mana cost, X is considered to be 0.
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.