Marmaduke: I asked Marmaduke to pick a card, and he ate it.

What makes this Marmaduke good (no, really!) is its directness. This is who Marmaduke is. This is what Marmaduke does. He is a gaping maw. He is the Destroyer. He might be sad about a particular act for a little while, as he appears to be in this cartoon, but only because he knows he's made his people sad. And he likes his people! But he can't change what he is. If you give him a card, he's going to eat it. If you leave some food unattended, he's going to eat it. If you bring over an unfamiliar friend, he's going to eat your friend. If you are happy, he's going to eat that happiness. He doesn't mean anything by it. It's just the way things are.

Cartoons such as this show Marmaduke to be a fatalistic symbol, a metaphor for the consuming power of the natural world. All things are temporal and pass away. Why? Because Marmaduke fucking eats them.