Answer:
A weighty currency.
A desert oasis where money magically disappears from your pocket!
Which bow can't be tied?
If you're on a diet, smelling a fresh pan of brownies could be described as this.
What do cows tell each other at bedtime?
Iām hard as a rock and as light as a feather. Iām passed on to one another. Poor people need me and rich people have me.