Marveta, Poison Mixer

At the end of each player's turn, that player loses life equal to the amount of life they lost the previous turn not from this ability, then put that many experience counter on Marveta.
{t}, Marveta deals damage to each opponent
equal to how much life you gained this turn.
then deal that damage during each of their upkeeps for X turns, where X is the number of experience counters on Marveta. Only use this ability once.