Ms. Terwilliger murmured a quick incantation as the blob nearly reached our tent. An invisible wave of power shot out and knocked the golden glob back a few feet. Then it began making its way back toward us.

“Wonderful,” I muttered. She repeated the spell, but it was clear that was only a temporary fix.

“Can we trap it?” I asked. “There are a lot of stones around. We could make some kind of enclosure?”

“It’s burning right through the stones in its path,” said Eddie grimly.

Ms. Terwilliger gave up on the force spells and cast a freezing spell similar to what she’d used in the robot museum. She directed a blast of bitter cold toward the molten puddle, which halted in its tracks. Half of the blob began to solidify, though the other half was still liquid and mobile and tried to wriggle away, dragging its frozen half with it.

“Sydney, get to the other side!” Ms. Terwilliger said.

I hurried to obey, running out of the tent and standing on the other side of the blob, which had liquefied now that she’d momentarily dropped the spell. The ooze moved toward the tent again, and Ms. Terwilliger held up her hands to cast. “On the count of three,” she ordered. “One . . . two . . . three!”

Simultaneously, we released freezing spells, attacking the molten gold from opposite sides. The mass wriggled and writhed in the grip of the magic but slowly began to solidify. I’d never sustained the spell for a long time, but Ms. Terwilliger wasn’t letting go of the magic. I followed her lead until, at last, the gold was still, completely solidified into an irregularly shaped puddle. We let go of the magic and carefully walked up to it. The gold stayed as it was.

“That was weird,” I said. “Not quite as bad as the last attack.” I still had a few cuts from the little magical fireflies that had come after us in Pittsburgh.

“Only because it didn’t get to us,” warned Ms. Terwilliger. “I hate to think what would’ve happened if we’d all been asleep in that tent when it liquefied.”

I shuddered, knowing she was right. “But what does it mean?”

No one had an immediate answer, but Eddie surprised us when he spoke a few seconds later. “I’ve seen this before.”

“A golden brick that turned into a deadly, rampaging puddle of molten metal?” I asked.

He shot me a wan smile. “No. Look at that shape. Doesn’t it seem familiar?”