Entertainers are one of the four basic classes of employee that the player can hire in Roller Coaster Tycoon and it's subsequent games. They take the form of costumed persons whom wander the park aimlessly and occasionally do a trick or otherwise do a short performance. Their presence generally functions to increase the park rating and increase the happiness of guests nearby. This can be used to great effect to keep guests in long queue lines from getting impatient or unhappy by assigning entertainers a patrol path restricted to a queue line.
Entertainers have multiple costume options which can be toggled at the whim of the player via a drop-down menu in their individual control panel. At minimum they have 3 costumes, but more are unlocked with certain scenery and theming scenarios (ex; researching Classical Roman Theming Objects allows the player to select a Roman warrior costume for the Entertainers.)