Darkness Grace?

[Pokemon--Foo]

If my opponent had an active spiritomb with 0 damage on it can he/she use its darkness grace attack to evolve a pokemon on the bench if he/she has none to evolve?
If not would he/she still put one damage counter on spiritomb?
Thanks

[PokePop]

You can always use any attack that you can pay for.
However, it would have no effect and since no Pokemon would be evolved, yuo don't put a damage counter on Spiritomb.