NOTE:I have not personally tested this idea, for the mere fact that I only
have 1 copy of each of Eevee's evolved forms and no Devolution Spray.

        The Devolution Spray has got to be one of the worst cards in the
Pokemon Card Game. After all, who would want to deevolve the Pokemon they
worked so hard to evolve? However, with Eevee, the multi-evolving wonder,
good use of the Spray could actually strike a surprise attack on your
opponent.
        Say that you have an evolved Flareon as your Active Pokemon in a
Fire/Electric deck. The Flareon has 2 Fire & 2 Electric energies on it.
Your opponent, trying to stop your Flareon's fire attacks brings out a
water Pokemon to snuff it out. On your turn, if you have the right cards,
you can smile, use the Devolution Spray on Flareon, get rid of any effects,
and then place a Jolteon card on Eevee instead. Suddenly, your opponent's
water Pokemon is toast.
        That is the best use of the Devolution Spray I can think of. If
anyone else has any good uses for it, please contact me.

-Jeff Groves
sendero@netins.net