BargainBargain is a static ability that functions while the spell with bargain is on the stack. “Bargain” means “As an additional cost to cast this spell, you may sacrifice an artifact, enchantment, or token.” Paying a spell’s bargain cost follows the rules for paying additional costs in rules 601.2b and 601.2f–h.
If a spell’s controller declares the intention to pay that spell’s bargain cost, that spell has been “bargained.” See rule 601.2b.
Objects with bargain have additional abilities that specify what happens if they were bargained. These abilities are linked to the bargain ability printed on that object: they can refer only to that specific bargain ability. See rule 607, “Linked Abilities.”
If part of a spell’s ability has its effect only if that spell was bargained and that part of the ability includes any targets, the spell’s controller chooses those targets only if that spell was bargained. Otherwise, the spell is cast as if it did not have those targets. See rule 601.2c. (CR 702.166)
When Dunbarrow Revivalist enters, you get a one-time boon with "When one or more creatures enter under your control,
createTo create one or more tokens with certain characteristics, put the specified number of tokens with the specified characteristics onto the battlefield.
If a replacement effect applies to a token being created, that effect applies before considering any continuous effects that will modify the characteristics of that token. If a replacement effect applies to a token entering the battlefield, that effect applies after considering any continuous effects that will modify the characteristics of that token.
Previously, an effect that created tokens instructed a player to “put [those tokens] onto the battlefield.” Cards that were printed with that text have received errata in the Oracle card reference so they now “create” those tokens. (CR 701.7) a Wicked Role token attached to one of them." Then if Dunbarrow Revivalist was bargained, return a creature card from your graveyard to your hand.