When the Children's Television Workshop unleashed Sesame Street on the world in 1969, it sparked a revolution in television programming. For the first time, TV was supposed to educate children as well as entertain them — make learning fun, using techniques developed through years of rigorous research. Parents across the U.S. had a TV show they could feel safe letting their kids watch.

When you buy the first season on DVD or iTunes today, though, it comes with a warning:

These early Sesame Street episodes are intended for grown-ups, and may not suit the needs of today's preschool child.

For parents today, especially those who grew up in the 1970s and '80s, this is not your child's Sesame Street. For one thing, Sesame Street has become pretty gentrified over the past 45 years — New York provides some examples. For another thing, "Prozacky Elmo didn't exist," says Virginia Heffernan in The New York Times Magazine, in a remembrance that both playfully mocks today's heightened sensibilities and notes some real differences between the Sesame Street of yore and today's more sanitized version.

"Oscar seems irredeemably miserable — hypersensitive, sarcastic, misanthropic," Heffernan notes. "Bert, too, is described as grouchy; none of the characters, in fact, is especially sunshiney except maybe Ernie, who also seems slow."

Sesame Street's current producers also cite Cookie Monster's dietary choices (including a pipe, after he smokes it for a while), the children shown riding bikes without a helmet and running through a construction site, and, in the opening scene of the very first episode, a young girl being shown around Sesame Street by a grown man, Gordon, who is not her father and is holding her hand.

It's true that most of those things wouldn't make it on children's TV today. But those aren't the only strange or even slightly disturbing early Sesame Street moments that wouldn't pass muster with today's sensibilities.

Here are 10 clips from a very different time, and a very different Sesame Street:

1. Kermit screams at and threatens Cookie Monster

The iconic frog used to be much meaner. Making Cookie cry? Telling him he's stupid and nobody will ever play with him again? Not cool, Kermit.

2. Bob gets trippy... and creepy

Not only is dulcet-voiced Bob wearing a groovy shirt and hanging out with (vaguely stoned-looking) hippy Muppets while singing a song from Hair — Hair! — but he's snuggling with a very young-looking Muppet girl while crooning about his "lover." Bob looks young here, but not that young:

3. The girl with fat knees

Credit where it's due: Sesame Street was talking about childhood obesity before it was cool to. But this isn't how Michelle Obama would go about it — or anyone else today:

4. A baby's living nightmare

A baby climbing a tall ladder, crying for help, then being rescued by a giant clown? No. Just no.

5. A child-hunting mutant rabbit?

You can file this under living childhood nightmares, too.

6. Accidental terrorism

Sure, the bridge the man accidentally blows up gets fixed in the end, but aren't you supposed to teach kids about taking responsibility for their mistakes?

7. Cookie Monster makes a sandwich

What's so odd about that? A sandwich is probably healthier than a cookie, right? Check out this egg salad recipe.

8. Lost in wonderland

If you want kids to experiment with hallucinogenic substances, show them this.

9. Ernie and the criminal

Kids, if a strange man approaches you and starts to open his trench coat, run.

10. Cookie boogies down at Studio 54

This obviously wouldn't fly today because disco's a little passé. But also: Kids may not know what went on in late-1970s discos, but Sesame Street's producers did. Why, exactly, did Cookie lose his "cookie"?