Wick, the Whorled Mind summon rat swarm instead of Rat plague token, when another rat enter the battlefield. Tested with Relentless Rat, Daggerfang Duo, another reinforcement of Wick, the Whorled Mind, all with the same outcome of having Rat Swarm token instead of Rat Plague token.
All the testing done above is not under the event Plague control: infestation.