What happens when Steven gets a hold of a time-travel device? He forms a band with himself!

This whole episode is basically that one gag building up and up until it crashes down in a blaze of glory.  There is no logic, only Steven.

Steven: How bout this one?

Pearl: What one?

Steven: This little one. It’s adorbable.

Pearl: Steven, the Legendary Glass of Time won’t be nearly so small and insignificant. It’ll be beautiful and grand!

But when Amethyst picks the wrong one and the temple starts flooding (as magical temples for legendary artifacts are wont to do), Steven grabs it anyway just because it’s adorbable and fits in his pocket. Naturally, it turns out to be the real one.

Steven: Thing! You took me back in time, didn’t you? Oh man! Pearl’s gonna flip when she finds out you were the real one.

I would be very curious to hear what the Crystal Gems had intended to do with a time machine – my guess would be that Garnet just wanted to keep it out of the wrong hands, but Pearl seemed a lot more invested in the idea (Amethyst evidently doesn’t care one way or the other).

But at least it takes one relatively minor mishap for Steven to conclude that he shouldn’t run around trying to change the past.

Steven: Future Steven?

Steven: Listen, Two Minutes Ago Steven. We can’t go around trying to change time stuff. It just makes things worse!

Steven: Aw man, I really wanted to play at Beachapalooza! Too bad you and I can’t be in a band.

Both: Wait a minute!

Can’t you see it in my eyes
I’m the one, I’m the
One!
Two!
Three!
Four!
I’m not like the other guys
(he’s not like anybody else)
That’s not completely right
There’s a few that I’m just like
Steven and the Stevens
We’re gonna make you smile
Me myself and I and him
Are all the same guy

There’s just something about Steven harmonizing with himself…

Anyhow, it doesn’t take too long for drama to catch up with the Steven band, particularly when Steven tries to pigeonhole himself into the band roles.

Steven: Hey, if Steven 1 is the handsome one, does that mean the rest of us aren’t good-looking?

Turns out Steven defies compartmentalization!

Steven: I can’t believe it. I’m so…annoying.

Steven: Whoa, what’s all this noise? I thought we agreed that Steven and the Stevens was going to be a light-hearted throwback to early rock and roll, not this mess of screaming and distortion!

Steven: Look, Steven. Steven and I were talking, and Steven agrees: Your attitude just isn’t working for us.

Steven doesn’t take this mutiny lightly.

Steven: Listen up! You can’t kick me out of the band! I’m the original Steven! I created you! Steven and the Stevens was my idea! Without me, you’d all be nothing – that’s it!

And then he tries messing with time again by warning himself not to start the band, but all of the Stevens have their own time things, so it just turns into a chase through time with no particular objective as Steven gets to be more and more unhinged (and more and more Steven time clones are created at every time jump).

Finally, he realizes that the only way to end the madness is to prevent himself from taking the time-glass in the first place.

Steven: Stop it! Look around you. This isn’t right. When Steven fights Steven, who is the winner? What have we become? We’re not the Stevens we once were. And to fix that, I have to end it!

These are all appropriate responses.

But when Steven finally just smashes the (original) time thing, all the other Stevens gradually melt away in the sands of time, leaving but one very confused little Steven.

Steven: Stay cool forever, Steven.

Of course the real solution was right under his nose, or would’ve been if he hadn’t had a magical artifact granting his wishes.

We’re not like the other guys
(we’re not like anybody else)
By the way, don’t go back in time
Or you’ll destroy yourselves
Steven and the Crystal Gems
We’re gonna make you smile
I accidentally created an alternate timeline
Steven and the Crystal Gems
C’mon now don’t be shy
I learned to stay true to myself
By watching myself die

Stay cool forever, Steven…