"...I wonder if I can do a generic magic blast. I'm supposed to have my own magic aside from the cards, maybe. Or I could try sealing it as-is, which also probably won't work."

"How would you do that?" Sadde unchanges the stick and crouches close to the ground to peer at the connection.

"Meditation and willpower? Meditation is supposed to help, and I've gotten way better at, hm, not-quite-meditating."

"Makes sense, I suppose," she says. "This card's good at what it does, the bits at either side are really similar."

So he sits down and meditates and tries to reach-without-reaching at the edges of the Loop's affected area.

The Loop's magic is very very subtle, he probably wouldn't have noticed it if he weren't right there in front of the edge. Now that he does notice it, however, it seems to stretch in all directions, subtly altering space itself to conform to the closed loop it wants that park to be.

Any detectable weaknesses, holes, avenues of attack?

Nothing obvious. The loop seems to be pretty deeply embedded into the fabric of space, very thoroughly linking different parts of the world, so perhaps targeting that could do something.

"Hum. There's nothing physical about it anymore, so of course the sword didn't work. Can Change change other cards? Time and space? Well, probably not time."

"I... haven't actually ever tried anything like that? What would I even target?"

"The place where the line is."

"Alright, let's try that." Sadde raises Change in front of his face and intones, "Turn the place where Loop folds space to metal, Change!"

The card glows and a patch of ground at the intersection starts glowing, as well, and is transmuted into metal, connecting both sides through the red line. The space around them starts to shimmer as if underwater, and suddenly the fold breaks, fading into the actual continuation of the park. And floating there, mid-air, is a red Möbius strip, twirling.

Even though it doesn't seem to be trying to escape, quickstep, tap, "I command you to return to your power confined, Loop!"

Unearthly wind, glowing lightshow, the strip dissolves into a card at the tip of the staff—

—and floats over to Sadde's hand. "Um."

"-Because you flushed it out, I am assuming. I'll ask Kero."

"Yeah. Um." Sadde offers it to Terry.

Terry attempts to take it, half-suspecting it'll just go right back to Sadde.

It does not, in fact, go right back to Sadde. It acts just like an oversized not-quite-cardboard card would, i.e. it does not do anything at all.

Sadde uses this time to turn back into a girl.

"Right then. That was interesting but it's high time I went and did some homework. I'll email you what Kero says about the card going to you."

"Okay. Have fun with homework? I hope your parents don't give you too much of a hard time?"

"Oh I'll be fine up until the moment when I actually fail to get a B or better. Tomorrow I should be more free, see you then?"

"Well, it could be worse, then, I suppose. And yeah, tomorrow!"

And he walks home and tells Kero about their little adventure and the card's confusing behavior and emails the analysis to Sadde and does homework, adequately, and programs a bit to distract himself and sleeps and goes to school and goes to find Sadde in the same park.

Kero explains that the card goes to whoever compelled it to show itself and/or did the most active work towards bringing it to a state where it can be captured, but other than that doesn't really express any preferences for people.

And Sadde's there again the next day!