The fuzzy bag of goo in question is, as shown above, the caterpillar of the Hickory Tussock Moth (HTM), Lophocampa caryae. I've received more than a few queries about these hirsute white cats, and so have many others. Perhaps you've seen one or many yourself this summer.
When seen marching across the ground, seemingly with a purpose, the caterpillar is probably near ready to enter the pupa stage and is looking for a good spot to build and secrete its cocoon. HTMC's overwinter in their cocoon phase, hidden in leaf litter.
This species has distinct boom and bust years, and at least in central Ohio this is decidedly a boom year. Rare would be the trip afield, right about now, where a sharp-eyed observer would not see some HTM caterpillars. Nothing to be alarmed at, though, as they'll not do any lasting damage to the trees, at least insofar as I'm aware. But do be aware, sensitive people can receive a rather nettlelike rash from handling the caterpillars. The effects are normally mild and fade fairly quickly. A good rule of thumb with caterpillars is to NOT HANDLE them, especially hairy or spiny species. Many species, such as this one, are armed with stinging hairs as a predator deterrent.