Oops
Explanation
This comic shows a panicked father exclaiming "Oh my God! I just dropped him but I thought he'd be okay! Oh my God!" while a small child stands nearby looking unhurt but annoyed. The joke is a misdirection -- the reader initially assumes the father dropped the child and is panicking about the child's safety. But the child appears perfectly fine, making the father's extreme reaction seem overblown.
The caption at the bottom reads: "You can paint a seedless watermelon to look just like Jigglypuff." This is a classic SMBC non-sequitur bonus panel caption, completely unrelated to the main comic, adding an extra layer of absurdist humor. The main comic's humor relies on the gap between the father's catastrophic emotional reaction and the child's apparent total lack of injury, poking fun at the tendency of new parents to massively overreact to minor incidents.