The most common objects that are swallowed by pets and require surgery to remove are: balls, bones, chew toys, corn cobs, hair ties, ribbons, panty hose, rocks, socks, sticks and underwear!
Dogs are very oral; they don't have hands to investigate, so they use their mouth. They chew for entertainment, to clean their teeth and to strengthen their jaw muscles. The reasons that dogs may be attracted to personal items, such as underwear and socks, is that the odor reminds them of their owners.
Cats, on the other hand, are not natural chewers, but they do enjoy playing with string-like objects, which are also dangerous if swallowed. Ribbons and hair ties are appealing to cats because they move in a way that a rodent moves.
These are the signs that your pet many have swallowed something and have an intestinal blockage: diarrhea, drooling, lethargy, persistent vomiting or dry heaving, refusing to eat, restlessness.