1x23 - Leave It to Beaver

Beaver makes a trade with Larry Mondello: a glass doorknob for a Chihuahua. Larry found the dog in his garbage can, so when Beaver brings it home, Ward immediately breaks the news that he's going to place an ad in the lost and found and that Beaver probably won't be able to keep the dog. Despite this, Beaver quickly begins to grow close to the little pooch.