Orneryboy - The Day After

Lore note: Brian is a zombie, and the cat is a Lovecraftian entity.

Comic strip by Michael Lalonde. The URL referenced in the images is down, but the artist put the entire series on archive:

• https://archive.org/details/orneryboy-michael-lalonde/ - look for the PNG options under "downloads"
• about the artist and this series: https://www.michaellalonde.com/comics/orneryboy/