When it comes to this fuzzy caterpillar, you can look, but you sure don’t want to touch.

Poisonous caterpillars, known as puss caterpillars, are once again popping up in Florida, and officials are warning residents not to be fooled by the creature’s soft and furry appearance.

It’s the most venomous caterpillar in the U.S. and even a simple brush with the insect can cause “excruciating pain,” according to National Geographic. The caterpillars’ fur hides toxic spines that stick to your skin.

One mom in Plant City, Florida, learned that lesson the hard way last week when her 5-year-old son accidentally stepped on one as he played outside.

“He started screaming, screaming and screaming,” Staggs told CBS News. “He screamed, ‘Get them off me!'”

At first, Angela Staggs thought her son walked on a pile of ants. She carried him to the bathroom and examined his foot over a bathtub, but there were no bites.

“He started to hyperventilate from screaming, and I was trying to figure out if he got into stinging nettles, but this scream was blood-curdling,” Staggs said. “Then it clicked…” Staggs told her dad to go outside to look for a caterpillar. “He comes back in and says ‘there’s a fuzzy looking thing out there, but I don’t think it’s a caterpillar.’”

“When my dad said a ‘fuzzy-looking thing’ my heart dropped,” Staggs said. “I knew exactly what it was before I even got out there.” When she ran outside, she saw the poisonous puss caterpillar on the porch, which her son must have stepped on after taking his shoes off to go inside.