Yep, Sin does take longer than five minutes.

Flying it is!

That cage sure is shaking a lot, though.

Well he isn't flying very far away, but that's a little worrying so he returns to Kaede and co and asks, "Does anybody know what elemental type that fiend was? If any?"

"It does not have any elemental weaknesses."

Did the fiend have wings?

Nope.

Oh it just looks like a weird scorpion, okay.

… He'll just go fix the box.

Well the box isn't broken per se but it sure does look like that might only be a matter of time—there are some dents.

Un-dent it. He'll un-dent it and make it thicker.

That causes the poor fiend to be unable to leave its cage. Rude, Theo.

He feels just terrible about that.

The cage continues swinging but significantly less wildly and dangerously than it was doing.

That's very nice of the cage.

Theo is less bored. He can wait around a bit more.

After about an hour of poking the Sinspawn, they can notice a suspicious amount of deep sea activity.

Okay, so Theo thinks he will go sea-wards. And scout. Unless there are any objections.

Black tendrils start to extend right under the water's surface, and a growing bump appears in the distance, like a giant wave. Everyone is too busy getting ready for battle to object.

That is unfortunately too far for him to affect.

He thinks he'll go closer. It's a good thing Kaede has his phone.

It's not too far for too long. The bump reaches the shore in a few more seconds and then—

—bursts—

—and Theo finally gets a good look of Sin.

Can't change it directly, can he?

Nope!

There seems to be a black rippling forcefield enveloping its body; through it he can see some nonmagical things that ended up sticking to its carapace. Maybe he can affect those?

If he finds the time, of course. The Al Bhed start firing cannons at it, and small waterborne crustacean fiends start dropping from its skin as the shots find their target. The Crusaders charge into the water to fight these fiends, and the giant Al Bhed laser starts visibly charging.

It's messy.

He tries to change some of the nonmagical things attached. What does it do if he ramps up the temperature, as quickly as he can, on some of those nonmagical things?

(He can't do it ridiculously quickly, but he can do it reasonably so – it takes a couple of seconds to get water to boiling in kitchen quantities.)

Nothing. The nonmagical things are coral.

Sin sheds its "skintight" black forcefield and creates another one, spherical, purple, around its body—

And if he tries heating up the air a lot? Tries turning the forcefield to air? Tries turning air above it into water in case it's really weak?

—and it shoots some of its forcefield out towards the people fighting finds in the water, turning them to dust.

(None of that works, no.)