|“||You're wasting your time. Factoring in sleigh speed, time zone changes, and reindeer bathroom breaks, it is scientifically impossible for this so-called Kris Kringle to deliver gifts to the approximately one billion qualifying children. As you can see, X equals no stinkin' way.||”|
— Lisa on why she doesn't believe in Santa Claus
Lisa Marie Loud is one of Lincoln Loud's ten sisters in the Nickelodeon animated series The Loud House. Although she is the second-youngest of the Loud siblings, at only four years old, she is also the smartest, having graduated college with a PhD and received a Nobel Prize despite her age. Speaking with a lateral lisp, Lisa spends her time invested in research, projects, and working on complex experiments, which often involve using her siblings as test subjects.
Appearances in Christmas specials
Lisa's first time appearing in a Christmas production is, of course, The Loud House's second-season premiere, "11 Louds a Leapin'". Early on in the special, Lisa expresses disbelief in the existence of Santa Claus, showing her notes about this, and continually remarks to Lola that she is only wasting her time trying to get herself on Santa's nice list. Perhaps because of this, she is noticeably the only Loud sibling who does not have a Christmas stocking hanging on the wall. When Lincoln tells his sisters all about Mr. Grouse being unable to visit his own family for Christmas, Lisa, who normally doesn't show her emotions, breaks down crying after hearing his story. After the Louds and the McBrides present Mr. Grouse with a bus card so he can see his family tomorrow, and he allows them to spend Christmas Eve with him, Lisa responds by crying tears of joy. On Christmas morning, Lisa, having received a piece of a meteorite, admits to her family that she now does believe in Santa, as she managed to get a photo of Santa (actually Mr. Grouse dressed as Santa) leaving a present for Lincoln behind the couch.
In the online-exclusive Loud House short "12 Days of Christmas", in which the Loud family sings their version of the titular song, Lisa sings that her gift was "ten beakers mixing." The first time she says the line, she mixes a chemical that blows up in her face.
Lisa's next appearance in a Christmas special was the fifth-season episode "Season's Cheatings". Here, it is revealed that she is not considered an ideal choice for one's Secret Santa in the Loud family's gift-swap, because her idea of a Christmas gift is a stack of papers listing "pi worked out to the five-millionth decimal."
Lisa also appears somewhat prominently in its partner episode, "A Flipmas Carol". At the beginning of the episode, she and her father Lynn Sr. come to Flip's Food & Fuel to buy ingredients for the family's Christmas Eve dinner. Flip sells them chicken that Lisa notices is not fit for consumption. Later, just as Flip is going to bed, Lisa appears as the Ghost of Christmas Past (the irony of this being that Lisa is the Loud sister who is least likely to believe in the supernatural). She takes Flip to revisit the night he was swindled out of going to his middle-school's Christmas dance and lost his chance of dancing with his dream girl, which is what led to him becoming the con-man he is now. At the end of the episode, Flip, having seen the error of his ways, brings an actually-edible turkey for the Louds; Lisa deduces that it is indeed a legitimate turkey dinner due to the label on the packaging.
Lisa and her family also have a cameo in The Casagrandes episode "A Very Casagrandes Christmas". At the very end of the episode, the Louds show up at the Casagrandes' Nochebuena party because their van broke down while they were picking up Lori from college.