You know the old man you see in the club that clearly doesn’t fit in with the young and hip 20-somethings as he tries to dougie on the dance floor?

The NBA equivalent of that individual is Shaquille O’Neal.

Past his prime and not knowing that it’s time to hang them up, O’Neal signed a two-year contract on Wednesday with the Boston Celtics worth approximately $3 million.

With center Kendrick Perkins out until next February after tearing his right anterior cruciate ligament in Game 6 of last season’s NBA Finals, the Celtics lacked a serious inside presence. General manager Danny Ainge signed the injury-prone Jermaine O’Neal to the mid-level exception last month to help fill the void before adding Shaq for further insurance.

O’Neal’s attempt to ride the coattails of LeBron James for his fifth NBA championship fell short after the Cleveland Cavaliers were eliminated from the Eastern Conference semifinals by the Celtics last season.

With LeBron taking his talents to South Beach, O’Neal left Cleveland in hopes of latching on with a team that had a legitimate shot of competing for an NBA title.

But at 38 and nothing else to prove at this point, this would have been the perfect opportunity for O’Neal to bow out and retire without tarnishing his legacy.

“For me, it’s been a real thinking process,” O’Neal said before signing with the Celtics. “I came into the league very graciously and want to go out very graciously.”

During the twilight of O’Neal’s career, he’s turned into a better entertainer than basketball player, as proven by his continuous trash talking and budding television career.

It seems only fitting that O’Neal remains in the Eastern Conference with the Celtics so he can continue his verbal onslaught against Orlando Magic head coach Stan Van Gundy and center Dwight Howard.

In March 2009 while on the Phoenix Suns, O’Neal referred to his former coach as a “master of panic.” And last season, O’Neal took offense to Howard using the Superman nickname, firing a shot at the 24-year-old. “You tell me who the real Superman is,” O’Neal said. “Don’t compare me to nobody. I’d rather not be mentioned. I’m offended.”

So much for going out graciously.

When he’s not verbally assaulting players and coaches during the season, you can find O’Neal spending his off-season on the ABC reality show, Shaq vs., competing against the top athletes in their respective sports.

With each stop since his departure from the Miami Heat in 2008, O’Neal has gone through the same routine.

First, Shaq has to assign himself a nickname to correlate with his new surroundings. We had “The Big Shaqtus” in Phoenix, “The Big Witness” in Cleveland and “The Big Shamrock” or “The Big Leprechaun” is already in the works in Boston.

Next, O’Neal gives his standard quote on how he’s ready to play a supporting role in the team’s quest for an NBA title.

“I am honored to be joining the Celtics,” O’Neal said in a statement. “I have played against Paul [Pierce], Ray [Allen], Kevin [Garnett], Rajon [Rondo], and Jermaine [O’Neal] for many years and it will be great to be able to call them my teammates. I cannot wait to get to Boston to get started in pursuit of another championship.”

Lastly, O’Neal serves as a pseudo hype-man for the team’s best player, as if he was taking an indirect shot at former Laker teammate Kobe Bryant.

How long before Shaq dubs Rajon Rondo the greatest point guard in the NBA since Magic Johnson?

Let’s hope we remember O’Neal for being a four-time NBA champion, 15-time All-Star and one of the most dominate big men in the game and not just filling the void left by the departure of Brian Scalabrine off the bench.