“What’s an obstaple?” I asked.
“I don’t know. Like crawling through mud and jumping over stuff and things. I didn’t really read the website that closely. You’ll love it. I brought treats.” 

Now I was real excited to do obstaple racing and show off how good I am at getting dirty and looking cool in pictures. But I guess Mom didn’t read the website closely at all because she found out that the humans had to do the obstaples too.
“Oh, well I can’t do that,” Mom told the lady with the t-shirts. “I have a medical issue.” 
“Mom, what’s a medical issue?” I asked.
“It means that I’m wearing socks,” she said.