Mythical

Winning the lottery twice in a row is a mythical possibility.

The belief that mermaids exist in real life is a mythical idea.

The legend of King Arthur and his knights is a mythical story that has been passed down for generations.

The thought of a dragon guarding a treasure hoard is mythical.

The story of a magical potion that can grant eternal life is mythical.

The notion that a single person can change the world on their own is a mythical belief.

Unicorns are mythical creatures that are said to have magical powers.