Whenever another creature you control dies, you get an experience counter.
At the beginning of your end step, choose target creature card in your graveyard. If that card's converted mana cost is less than or equal to the number of experience counters you have, return it to the battlefield. Otherwise, put it into your hand.
11/4/2015 If Meren of Clan Nel Toth leaves the battlefield at the same time as other creatures you control die, its first ability will trigger for each of those creatures.
11/4/2015 You can’t choose to put the creature card into your hand if its converted mana cost is less than or equal to the number of experience counters you have as the ability resolves.
11/4/2015 If a creature card in your graveyard has in its mana cost, X is 0.
11/4/2015 Experience counters are the second kind of counters a player can have, joining poison.
11/4/2015 All experience counters are identical, no matter how you got them. For example, the last ability will count experience counters that you got from the first ability, from another ability, from proliferating, and so on.
11/4/2015 Each game pack includes a card labeled “Experience” with the suggestion “Place your experience counters here.” This card isn’t required for play. It’s simply a convenient spot to put your experience counters, which can be represented with dice, glass beads, or other small items.