The dangerous White Hickory Tussock Moth Caterpillar, that originates from Canada, has made its way into Pennsylvania, according to WPXI News. The caterpillar is white and fluffy, and possesses black spines that excrete poisonous venom.

Those who come into contact with the caterpillar will likely break out into a rash - if this happens, treatment with lotion and ice is usually enough to make symptoms subside after a few hours, according to ABC News.

"There have been many reported cases," said Josepj Betz with MedExpress. "None of them fatal, but all strange, new and concerning."

The poisonous spines are an evolutionary adaptation meant to ward off predators.

"They don't mean to do it, but it is part of their defense mechanism against large predators and toddlers," said Betz.

The White Hickory Tussock Moth Caterpillar originates from southern Ontario, Canada, where it had naturalists concerned back in October 2013, according to CBC News.

"For a long time I just thought it was a cute little fuzzy caterpillar," said Paul Pratt, of Ojibway Nature Centre. "Recently I found out they're actually venomous."

"Just like monarch butterflies are bright and orange because if a blue jay eats one, it'll throw up," he said. "So, they're advertising, 'I'm distasteful.' The caterpillars are basically doing the same thing."

With winter approaching, the caterpiallars are expected to go into hibernation.