More Riddles!

What will make the barrel lighter if you put it in a barrel?

He got me in the forest. He sat down to seek me. He couldn't find me, so he took me home.

Walk on the living, they don't even mumble. Walk on the dead, they mutter and grumble.

I can ruin cars and make swords crumble. Yet for all my power, I can't harm a club.

I have a name, but if you say it I'll disappear.

Two sisters, one dark, one fair. In twin towers dwelling. One from land and one from sea.

When you need me you throw me away. When you don't need me you bring me back.

When you don't have me, you want me. But when you do have me, you want to give me away.

I have lakes with no water, mountains with no stone, and forests with no trees.