comic- or tragic-strip?

webster distinguishes the comic from the tragic, but if there's a line, the authors of get fuzzy and FBoFW blur it a bit of late. i'm not criticizing anyone, free speech 'n all (no hate spam please), but i remember this happening w/ calvin and hobbes from time to time, and i wonder whether anyone else has pondered what happens when comics turn serious. it's not that they're suddenly tackling "real-life issues" b/c they do that all the time; it's just that they normally make me chuckle when they do it. anydangway, i was just curious.

(a free snickerdoodle to the first person not named dennis to identify the un-cited comic reference above)