It's that time of the year again, when fluffy caterpillars can be seen all across San Antonio. While they might look cute and harmless, keep your distance. The insect is actually venomous and can be harmful to everyone, especially children.

You might hear or see them referred to as an asp caterpillar, puss caterpillar, or southern flannel moth caterpillar, but what you really need to know is what they look like and why you shouldn’t touch them.

“They have spines underneath their body that have venom glands, so when they land on you those spines can dislodge and get stuck in your skin and that venom just kind of trickles out like a stinger would and you can react to that pretty badly,” said Molly Keck, an entomologist with Texas A&M AgriLife Extension.

Keck noted that the puss caterpillar comes around San Antonio every year during the fall. KENS 5 found some at the Medical Center. Keck said that they like Oak and Elm trees.

“Where you have them, usually you have a lot of them. So you probably won’t see one in a tree. There’s going to be others around. So there’s going to be parts of town that have higher populations than others,” Keck explained.

The sting can be extremely painful and, depending on the person, the allergic reaction could even be life-threatening.

“The venom can still hurt you when they're dead. So even when you treat them and they fall out of the tree dead, don't even pick one up if it’s dead,” Keck warned.

Keck also said that, overall, people shouldn’t be fearful, but be aware, especially children who might think it’s okay to pick one up.

“I did see a record that in 1923, schools actually had to shut down in San Antonio because there were so many of them on the playground,” Keck recalled. “I hear about that all the time across Texas. They’ll be in the oak trees, falling on the slides and things, so kids can’t go outside.”

In 2014 and 2015, Reagan High School students were taken to the emergency room after being stung by the caterpillars. Keck said that it's probably safe to say the caterpillars will be around for a few more weeks.