Family Guy: Season 10, Episode 14

10 - 14: Be Careful What You Fish For

When Peter and the guys try to salvage a sunken Mercedes-Benz, Peter half-heartedly promises a favor to a helpful dolphin. Soon the dolphin moves to Quahog, outstays his welcome at Peter's and moves into Cleveland's house across the street. Peter tries to reunite the dolphin with his ex-wife in hopes that he'll return to the ocean, but his plan backfires and the whole dolphin family moves into Cleveland's.