In a tunnel of darkness lies a beast of iron. It can only attack when pulled back. What is it?

Answer: A bullet.

More Classic Riddles with answers

More Classic Riddles

In camps about the centre I appear; In smiling meadows seen throughout the year; The silent angler views me in the streams, And all must trace me in their morning dreams, First in the mob conspicuous I stand, Proud of the lead, and ever in command. What am I?
In spring I am gay in handsome array; in summer more clothing I wear; when colder it grows I fling off my clothes; and in winter quite naked appear. What am I?
In what year did Christmas Day and New Year's Day fall in the same year?
Inside a burning house, this thing is best to make. And best to make it quickly, before the fire's too much to take! What is it?
Iron roof and glass walls, burns and burns but never falls. What is it?
It goes through the door without pinching. It sits on the stove without burning. It sits on the table Not ashamed. What is it?
It goes up, but at the same time goes down. Up toward the sky, and down toward the ground. It's present tense and past tense too, come for a ride, just me and you. What is it?
It runs and runs but can never flee. It is often watched, yet never sees. When long it brings boredom, When short it brings fear. What is it?
It speaks with a hard tongue, it cannot breathe, for it has no lung. What is it?
It stands on one leg with its heart in its head. What is it?
It's been around for millions of years, but it's no more than a month old. What is it?
Jack has 8 bricks 7 of them weights the same amount and one is slightly heavier. Using a balance scale, how can Jack find the heavier brick in two weighings?