After a few minutes arguing about whether he actually ate the sock or just hid it somewhere when we weren't looking, we finally decided that we should call the vet. The friendly lady that answered the phone suggested that we induce vomiting by giving Tyler a few tablespoons of hydrogen peroxide.
So we did. Kelly held him and I poured a shot down his throat.
3 minutes later - success! Completely disgusting success:
Eric - (just walking back outside) - "Has he puked yet?"
Kelly - "Yeah - but I need something to poke through the massive blob."
Eric - "OK." (picks up a stick from the yard that Tyler thankfully hasn't swallowed.)
Kelly - (staring at the vile, foamy mass in the grass) "Oh geez - is that it?"
Eric - "Ugh...I can't believe that's a sock."