LaPaz Home Learning

Superboy was hunting faeries last night in the forest. In order to get back home he needed to cross a bridge. As he approached to cross he was confronted by a Troll. In order to pass safely, he had to outwit him by means of a riddle contest. Here is the riddle the Troll presented:
“What has metal on the outside and flesh on the inside. No corners but two edges?”

Superboy, being a clever lad, solved this one easily, despite the troll’s disturbing habit of licking his lips in anticipation.

“A ring,” he guessed to the troll’s bitter regret.

After much stomping about and gnashing of teeth the troll admitted he had it right.
Then it was Superboy’s turn to try to stump the troll.

He asked him the following (made up on the spot):
“Flesh on top and soul below. Must be tied tight in order to go.”

The troll thought for awhile and then made his guess: “A dog on a leash,!!” he shouted with an evil gleam in his eyes.
The troll was so confident in his reply that he immediately began grabbing for Superboy’s leg. Superboy had to unclench the troll’s clammy fingers from his ankle in order to inform the troll that his guess was wrong.
This sent the troll into a mighty fit of wailing and crying. He knew he had to let Superboy pass and went splashing into the creek muttering loudly about missing his dinner. Superboy did not wait around to give him a chance to change his mind but fled quickly across the bridge and home!

So… anybody think they can outsmart the troll and guess Superboy’s riddle?