It was cutting my grass when I noticed an unusual clump on a Walnut tree trunk. As I got closer it appeared to be a fibrous growth. Then I noticed them moving. I did a quick Google search and learned what these are. I also found out this about them
The caterpillar excretes a type of chemical defense upon contact (which is more 'allergenic' than 'poisonous'). Most people who handle these critters will experience a burning, nettle-type, itchy rash of mild to moderate severity, and washing the affected area with soap and water, then applying ammonia or calamine lotion and icing the area should set things to rights.
