Don Nelson brought Hack-a-Shaq into the modern game, although it actually originated with Wilt Chamberlain back in the 1960s. Wilt was such a bad free-throw shooter that teams would literally chase him around the court trying to foul him, even when he didn't have the ball. This unwatchable game of tag led the league to alter the rule, which now allows any player to take the free-throw and the fouled team to maintain possession.
Nellie first started using it against Dennis Rodman (without success), and then started a trend in 1999 when he began his successful assault on Shaquille O'Neal. So next time a game takes 25 minutes too long, you know who to thank.