What do you call a contract where one party may benefit significantly more than the other?

The correct answer is the aleatory contract. An aleatory contract is characterized by an arrangement where the performance of one party is dependent on an uncertain event, which can result in unequal benefits or losses between the parties involved. In many cases, one party may receive a significantly larger benefit or payout than the other based on the occurrence of that uncertain event.

The other types of contracts mentioned do not have the same implications regarding unequal benefits. A conditional contract is based on specific conditions being met, but does not inherently involve one party benefiting more than the other. A contract of adhesion typically refers to a standardized agreement where one party has significantly more power in the negotiation, which can lead to imbalances, but it does not directly imply unequal benefits based on an uncertain event. A unilateral contract involves one party making a promise in exchange for an act by the other party; this situation may not inherently lead to unequal benefits since the outcome depends on the action taken by the second party.