Aha! Finally one I recognize and I am on time to say so.

This is Barb Pillsbury's Smallville Players III: The Final Curtain .

Quote
He closed his eyes, briefly, praying for her image to leave him and
stop playing tricks on him; but when he opened them again, the mirage
was still there, dark pools in its eyes, colour-drained cheeks, and
Clark's super senses picked up the sound of a racing heartbeat.

But...

Mirages weren't supposed to have a heartbeat!

A sudden shiver ran through him as he stood still, unable to move,
frozen into place, and watched the origin of his sudden unease look
frantically for an escape. But it couldn't be... *she* couldn't be...

He was experiencing a weird feeling, something new... no, not new, he corrected.
Something experienced long ago and now buried deep inside him,
something that had waited until this moment to bubble up back to the
surface of his subconscious and grasp at his senses, something he
hadn't been able to feel for months. A rush of adrenaline coursed
through his whole body, making his head spin and leaving him slightly
dizzy; an abrupt acceleration of his heartbeat, knots tying
themselves in the centre of his chest.

No mirage.
Saskia smile


I tawt I taw a puddy cat!