Zion is trying to figure out what humor is. It's interesting and annoying at the same time. Most of his forays into humor are both confusing and tiring. For example, from several days ago:
Zion, mumbling: ...I'm going to shoot Liel's robot, Mommy!
Me: No, you're not, Zion.
Z, laughing manically: Oh, it was a joke!
Me: Well, it wasn't a very good one. Jokes should be funny.
Z: There's a shirt that says dingo snack! It's a joke! (more maniacal laughter)
This scene is repeated many times a day. The only variable part is the beginning. Sometimes he starts out with the laughter, sometimes he says things that make no sense, and often he says things that he knows aren't kind or appropriate behavior. So he's testing out those boundaries, too.
Of course he's unintentionally funny all the time! This afternoon we were reading about squirrels and he said, "But aren't squirrels usually sick, mama?" "Sick?" I said. "Yeah. Don't they usually have radios in them...or something?"