The Grouch appeared in the quest The Missing Xmas Elves (Christmas 2013) and then re-appears in Sous Judgemental, a part of the Let's Eat Update 2014.
The Grouch is green skinned and wears a suit with a top hat. He dislikes fancy food and prefers disgusting foods, shown during the Sous Judgmental quest he eats a mud pie.
Sims can only interact with the Grouch when the goal during the quest tells you to. The Grouch will show up in your Sim's relationship list either as disliked or nemesis (depending on what Sim you used to interact with him) and will stay there.
The Missing Christmas ElvesThe Grouch used to be Santa's head elf, but he got jealous of Santa and quit. Every Christmas he thinks of a new way to ruin christmas. This time, he created the machine to suck all the Christmas spirit out of Sim Town! After your Sim sings carols, the machine cracks and the Grouch prepares to leave town. Your Sim can't stop there, though. After making The Grouch a present, you decide to, yet again, sing carols with him and tell him jokes. Finally, his machine exploldes and he leaves town.
The Grouch appears in the quest Sous Judgemental, he was the owner of the run-down restaurant, the Candelit Fork, until you came along! He has his very own 'Special Dish', which certainly is 'special'. After serving two judges, he is the third and final judge! It turns out that he loves mud pie, so you get a toddler to make one for him.
The Grouch is set to appear in the Christmas 2014 Event.