Even if you possess the absolute baseline of pop cultural literacy, you're probably aware of Garfield, that orange comic strip cat who's spent the past thirty-odd years terrorizing his man-child owner.
Garfield strips aren't heavy reading whatsoever — in fact, they make Marmaduke look like obscurantist performance art. This wasn't the case when cartoonist Jim Davis wrote "Primal Self," a shockingly creepy vignette for the 1984 book Garfield: His 9 Lives.
Most of the stories in His 9 Lives are light-hearted comics about Garfield's past incarnations throughout history (for example, as a cave cat or a viking). But in "Primal Self" — which features art by Jim Clements, Gary Barker, and Larry Fentz — things go off the deep end without warning. I read "Primal Self" when I was seven, and it messed me up for a solid week.
For the last few decades, that scene of the Sabertooth Tiger Volcano Hell Dimension has been tattooed onto my subconscious. Can you imagine Ziggy or Hi and Lois pulling this off? I mean, Mark Trail's beating the hell out of pot farmers these days, but even his reefer-busting can't hold a candle to this.
Of course, the strip that prompted this post was the infamous Halloween 1989 Garfield arc (at left, via Laughing Squid), wherein the lasagna-loving cat wakes up one morning to discover his life never existed.
And for more mental scarring, see "The Lab Animal" from the 1988 TV special adaptation of His 9 Lives. They didn't animate "Primal Self," for reasons obvious and childhood-destroying.