According to the Torah (the first five books of the Bible), if we find a lost ox or sheep, we must bring it back to its owner — and if we don’t know who the owner is, we have to keep the animal until it’s claimed. The same goes for other objects, including stuffed bunnies: “So shall you do with any lost article . . . you shall not ignore it” (Deuteronomy 22:3). It’s not enough simply to hold on to the object; you must keep it safe.
In Judaism, the mitzvah of returning valued objects to their owner, rather than keeping them for yourself or ignoring such objects is called hashavat aveida in Hebrew.