"Horses were coming around this corner. The crowds were scattering. It was very, very scary," a witness described.
Authorities said a 9-year-old boy and a 58-year-old woman, who were struck by the carriage Monday in Elm Grove, were taken to a hospital.
The boy suffered a minor cut and stomach pain. The woman suffered ankle, shoulder and head injuries.
"She was in between the horses and the wagon and it was lucky that they stopped cause the wagon would have ran over her," Greg Woolman, husband of the victim said.
A 77-year-old Milwaukee man was struck by the ponies but refused to be taken to a hospital.
The owner of the ponies said they've done hundreds of parades and nothing like this has ever happened.
Police said the ponies might have been startled by tennis balls that children threw or fireworks.
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