The Thing is an object that Mr. Big made in his debut episode. It is just a white cube and is pretty much useless, but Mr. Big uses mind-control in order to sell it. There is city-wide chaos as all of the citizens are fighting to gain as many Things as possible. Even Huggy Face is overcome by the temptation, as he tries to steal one of the cubes from a baby.
WordGirl is the only one who is not affected by the arrival of the Thing, and she pays Mr. Big a visit because she suspects foul play. Mr. Big describes the thing to our plucky heroine, but she is not satisfied, stating that his description was way too vague.
She is about to leave, confused as ever, when Leslie walks in and says she has the mind control ready. Mr. Big realized that the ray was not affecting Word Girl because it was in the wrong setting, and he was about to reset it when Word Girl was able to disable it. As soon as it was shut down, all the citizens in the city stop fighting over the Thing, throwing them out.
It is shown that the Thing is pretty worthless, although one of Mr. Big's rivals made a product very similar to it called "The Mega-Object", and it sold out in eight minutes flat without use of mind control. Mr. Big also made a product called the Mega-Thing, which is just a bigger version of the Thing, but Word Girl stopped him before it could be sold in stores.