The rules on what the "soft object" is are a bit vague. Standard matches have coaches throwing something like a spongey brick into the ring, but taking a page from Hollywood, the Olympics are taking the opportunity for what amounts to a little product placement. The stuffed animal is Vinicius, the Rio Olympics' official mascot.
In essence, the stuffed Vinicius is like the challenge flag thrown in the NFL. It's something the NFL should maybe consider adopting. It takes a little of the anger out of a challenge. How mad could you be if you were throwing a stuffed lamb in a bonnet onto the field?