caballito

diminutive of caballo: a little horse, horsy, pony; wheelie (an action or stunt where a bicycle, motorcycle, or other vehicle is ridden for a short period while it is standing only on its rear wheel or wheels); horsy (a game where a child rides on the back of another, who is on all fours); rocking horse (a child’s toy consisting of a (usually wooden) horse mounted on a rocker or swing); hobby horse (a child's toy consisting of a (usually wooden or cloth) horse's head mounted on a stick)

From caballo + -ito. * (wheelie): By imitation of horses.