When Dan Walsh, a 33-year-old technology manager in Dublin, started posting doctored versions of the comic strip “Garfield” on his blog in February, he thought he might amuse a few friends.

Instead, his site on Tumblr started receiving as many as 300,000 hits a day from the United States and beyond. More recently it has leveled off to 30,000 to 35,000 a day, which is not bad for a site whose content takes about five minutes to create.

Mr. Walsh does nothing to the panels except strip away Garfield and other characters  like Odie the dog and Nermal the kitten  to create a new, even lonelier atmosphere for Jon Arbuckle, the main human. Without the cutesy thought-bubbles of his lasagna-loving cat, Jon’s observations seem to teeter between existential crisis and deep despair.

“Do you have any unfulfilled dreams?” Jon asks in the first panel of the “Garfield Minus Garfield” strip posted on May 2. Then he stares into the void for the next two frames.