The Pink Teddy bear began its run as a major recurring motif in the second season. It was first featured in a webisode before the second season, in a music video for Jesse Pinkman’s band, TwaughtHammer.
The pink teddy bear is seen again in flash-forwards in four episodes: Seven Thirty-Seven, Down, Over, and ABQ, which — when put together — foreshadows the events of the season two finale: Flight 737 Down Over ABQ. (737 is also the number in thousands of dollars that Walt thought that he needed to support his family after he died).
Each flash forward from those four episodes is in black-and-white except for the pink teddy bear.
The teddy bear falls out of the downed 737 plane and lands in Walt’s swimming pool, losing its eye. In that second-season finale, Walt White — who had worn nothing but beiges and dark colors all series long — is seen wearing, what else? A pink sweater.