There's an accomplishment in the NBA that has only happened five times in its entirety and only four names belong on that prestigious list. The name on the list are Hakeem Olajuwon, Nate Thurmond, David Robinson, and Alvin Robertson. Olajuwon is the only player to make the list twice.
Now one may wonder what is the rarest accomplishment in the history of the NBA? The answer to that is averaging a triple double for an entire season. That has only happened once and that was the legendary Oscar Robertson.
But, for the NBA the second rarest accomplishment is the quadruple double. It's extremely rare and the last quadruple double happened over 15 years ago.