[BostonCard]

Not Canseco, McGuire, or Bonds.

Like Gary Carter, this player had a brief stint with the Giants but is most known for his career on another team.  He's a five-time all-star, two-time world champion, won two silver sluggers and was the AL RBI leader once (not in 1994).

BC

Joe Carter.

Well done!  Nice work as well by Terry to narrow it down a bit, under the assumption he won both WS with the same team (which he did).

Was tempted to misdirect by saying he was a Hall of Famer, but that would have been mean since he's in the Canadian HoF, not the one in Canton.  As a big Jays fan growing up, Carter was a big hero.  Of course, his Game 6 walk-off home run to win the 1993 world series is iconic:

1993 WS Game 6: Joe Carter wins Series with homer - YouTube

Who was the only other player to end a World Series with a home run?

Less known about Joe Carter is that he also ended the 1992 World Series by taking a throw from reliever Mike Timlin on a bunt, which was the first time the World Series ended on a bunt.  Who was the Atlanta Brave whose failed bunt attempt ended the WS? 

BC

[BostonCard]

Not Canseco, McGuire, or Bonds.

Like Gary Carter, this player had a brief stint with the Giants but is most known for his career on another team.  He's a five-time all-star, two-time world champion, won two silver sluggers and was the AL RBI leader once (not in 1994).

BC

Joe Carter.

Well done!  Nice work as well by Terry to narrow it down a bit, under the assumption he won both WS with the same team (which he did).

Was tempted to misdirect by saying he was a Hall of Famer, but that would have been mean since he's in the Canadian HoF, not the one in Canton.  As a big Jays fan growing up, Carter was a big hero.  Of course, his Game 6 walk-off home run to win the 1993 world series is iconic:

1993 WS Game 6: Joe Carter wins Series with homer - YouTube

Who was the only other player to end a World Series with a home run?

Less known about Joe Carter is that he also ended the 1992 World Series by taking a throw from reliever Mike Timlin on a bunt, which was the first time the World Series ended on a bunt.  Who was the Atlanta Brave whose failed bunt attempt ended the WS? 

BC