He is often seen in the background, playing with the other pets, especially Charles. Much like Charles and Lana, he enjoys playing in the mud, as shown in "Undie Pressure" when he and Charles roll in a mud puddle and "Game Boys", in which he enters the house with muddy paws.
Despite this, Cliff is a very affectionate cat, and loves the Loud family very much. He occasionally sits on the Louds' knees, sleeps on their beds, or even joins them at the dinner table.
Cliff is also shown to have a big appetite, even for human food. For instance, in "A Fridge Too Far", he eats all of the food that the Loud siblings threw away, which ends up making him vomit, and in the game Living Loud: Lincoln's List, Lincoln feeds him a cookie.
Appearance
Cliff is a full-grown, domestic, short-haired cat with black and blue highlighted fur, whiskers, a large black nose, a zigzagged tail and small ears.
One of the Lincoln Vlogs reveals that he was adopted because Lana found him and cried until they got to keep him, and that he was named after Cliff Sterrett in-universe as well as out-of-universe.
In "Head Poet's Anxiety", Cliff is present seven years ago (when Luan is eight) and appears to be a kitten. This reveals that he is about seven years old (since cats are considered kittens until they turn one) and that Lana found him when she was a baby.
"Home of the Fave" reveals that Cliff sometimes poops in Lynn Sr.'s shoes.
