The creepy crawlers are Gypsy Moth caterpillars, and they're chomping through tree foliage in forests, backyards even on college campuses.
"I jumped off my bike and I was covered with them," Deborah Bourne told CBS News correspondent Michelle Miller.
Forest ecology professor Sarah Webb says the caterpillars have decimated hundreds of Drew University's century old white oaks.
"Well, if you look up to the canopy here, the upper parts of the forest, you'll see it looks like an early spring or even winter in many places," Webb said.
Scientists are concerned because this is when trees are at their fullest and greenest. Those infested may not die immediately, but will be stressed into next season. Another round of these critters could wipe them out.
The non-native insects got here by accident.
A French entomologist hoping to farm silk brought them over in the 1860s. A few escaped and they've eaten their way from Virginia to the Great Lakes at a rate of five miles a year.
But this year they've feasted on the Mid-Atlantic, chewing through 200,000 acres in New Jersey, 50,000 acres in Maryland and 700,000 acres in Pennsylvania.
A naturally occurring fungus usually keeps them in check, but that's not so this spring because of unusually dry weather. Now eradicating them entirely is nearly impossible.
So, humans in the thick of it: count your blessings.
When the worst is over in a few weeks, unlike the trees, you'll still be covered.