He was relieved to know that Castiel wasn't someone that wanted people to fear him. That meant he was good, and that Peter's instincts were still holding true. His Spidey sense had not gone off, and he knew his choice in sitting down to have pizza with this guy was the right one.
The next statement floored Peter some. The Spider blinked, and took a bite or two of his pizza before his smile returned.
He was human. That was the truth. But not all human.
Peter set his pizza down, wiped his hands on his napkin and then lifted his arm quick. With the flex of a wrist, webbing shot out and covered Castiel's plate. Peter smirked and looked up at Cas, "Super-human arachnid."