The Toll Is Waived

The other side of the bridge beckoned, as I faced the troll.
"None pass without paying the toll," he announced.
"What's the toll? I haven't much time," I replied.
"You answer a question. If you're wrong, I get to eat you."
I had no choice. "Ask your question, troll."
His large green face lit up with glee.
"How long's a piece of string?"
"I've no idea," I shrugged.
He cheered triumphantly, reaching for his knife.
"You don't look scared," he said, confused.
"I've been poisoned, and the healer's on the other side," I smirked.
Dejected, the troll let me pass.