This is the only episode of the season I missed but I've always had a problem with the concept of Clark transferring his powers just by getting hit by lighting (it was used in other series such as "Lois and Clark") CK's powers come from his Kryptonian physiology (sp?) and so shouldn't pass on to humans.

Those meteor rocks can do strange things.

Yeah, it was a combination of the kryptonite and the lightening that made it possible.

One of the supervillains (Livewire) from the more recent Superman cartoon got her powers like that, too. Supes was struck by lightning, the electricty passed through him (y'know, apparently 'man of steel' means he conducts just as well, too) to a woman, and gave her powers.

In that Lois & Clark episode clarks
powers were not transferred but copied to the other guy when lightning hit them.
No kryptonite was there.

Gretchen later reproduced this process in the lab, copying the powers of the guy first to a mouse then to herself. The guy catches her and
they loose their powers when the process is "reversed".

Kind of the same happens again when superman rescues an airplane, was hit by lightning and a little boy, sitting at the window, gains his powers. These later fade away because of the plane's hull, wheren't copied completely or something like it.

When clark's powers actually get transferred (to lois) that's because he was hit by a red-kryptonite-laser.

Looking at "Leech", we could assume that the "meteor rocks" were responsible why clarks powers were transferred.