BOO! at the Zoo is a family-friendly event in which children ages preschool through elementary school can dress up and trick or treat alongside their favorite exotic animals at Zoo Knoxville. The dates are October 12-15, October 19-22, and October 26-29 from 5:30 p.m. to 8:00 p.m. The fee is $9 per person, and children 4 years and under are free. Be sure to check out the science experiments and demonstrations with the Ask A Scientist at UTK members.