Children splash care free in Clayton's Grove Park, but a warning from the health department has parents on edge.
The sick bat was found on a pathway in the park last week.
"It was positive for rabies," said Catherine Pierce, who served as a communicable diseases program chief in the army. "I mean that's terrifying ultimately."
It's a concern for Contra COsta health services too.
"Rabies is nearly 100 percent fatal in human beings, so once symptoms appear -- the person is going to die," Pierce added.
A man died in 2012 after exposure to a bat in Contra Costa County.
"By the time he developed symptoms it was already too late to save him," Pierce told ABC7 News.
There have been three rabid bats found in the county this year.
"The biggest indicator that an animal has rabies is that they're a night, a nocturnal animal and out during the day," said Pierce.
"I wouldn't touch it," said Clayton resident Justin Lee Haberlin. "You gotta get tested for rabies and rabies shots are no joke."
The Lindsay Wildlife Hospital treated the sick bat, but it died. They say you should never touch a wild bat. Instead, you should call animal services.
Click here to learn more about the Lindsay Wildlife Experience.