My Friend Catherine
My Friend Catherine
[Captions above the frame:] New favorite substitution: My Cat→My Friend Catherine
[A news feed with comments by six different people discussing their cat, but after the above substitution. Next to each post is a user image, and above the clear text of the substituted comment is a unreadable line of wiggles probably with information about the post time stamp.]
[A head shot of a person seen straight on with black hair:] My friend Catherine just did a backflip and then ate a bug!
[A full view of Cueball:] I wish my friend Catherine wouldn't wake me up by chewing on my hair.
[A head shot of Megan with unreadable text below the image:] Oh no, my friend Catherine has learned to open the refrigerator.
[A head shot seen from the front of Knit Cap:] My friend Catherine just walked in, threw up on the rug, and walked out.
[A head shot of Ponytail:] My friend Catherine is looking out the window making weird noises at the birds.
[Cueball seen from the torso and up:] I wish my friend Catherine wouldn't make eye contact with me while pooping.

This is another comic using substitutions to create the joke by replacing words or phrases, in this case "My cat", with a different word or phrase, in this case "My friend Catherine" (hence the title). The choice of the name is probably because "Cat" is a common nickname for "Catherine".
By doing so in a list of people discussing things their cat did , it makes it seem like they are discussing things their female human friend did.  What is cute (sitting on keyboards), impressive (doing backflips to eat bugs), or at least normal behavior for a cat (vomiting hairballs) would often be weird, disgusting or disturbing if an adult human were to do it, which is what makes the substitution humorous.
The comic depicts a feed on a page for people discussing their cat, similar to Twitter or Facebook, which would be the only kind of place where the substitution is really funny. Apart from known characters like two looking like Cueball , Megan and Ponytail , there is also a person with black hair, not looking particularly like any standard characters, and then a person with a knit cap , which could be the same knit cap wearing user that was also used in 1506: xkcloud (see the pictures of the users ).
[Captions above the frame:] New favorite substitution: My Cat→My Friend Catherine
[A news feed with comments by six different people discussing their cat, but after the above substitution. Next to each post is a user image, and above the clear text of the substituted comment is a unreadable line of wiggles probably with information about the post time stamp.]
[A head shot of a person seen straight on with black hair:] My friend Catherine just did a backflip and then ate a bug!
[A full view of Cueball:] I wish my friend Catherine wouldn't wake me up by chewing on my hair.
[A head shot of Megan with unreadable text below the image:] Oh no, my friend Catherine has learned to open the refrigerator.
[A head shot seen from the front of Knit Cap:] My friend Catherine just walked in, threw up on the rug, and walked out.
[A head shot of Ponytail:] My friend Catherine is looking out the window making weird noises at the birds.
[Cueball seen from the torso and up:] I wish my friend Catherine wouldn't make eye contact with me while pooping.
