Oh, for a second there I thought the ability was going to read, "Discard 1 W energy, your basic W pokemon do 30 more damage." But it forces a switch which isn't bad. Though i'll repeat it FORCES the switch on them, not a Lysandre effect, card would be busted and 6/5 wossies if it was that. Attack's not bad too, I could see it in Lapras as a prize-1 attacker and the extra 20 damage to everything else makes lapras hit those numbers harder.
Honestly not the best, there are better prism cards already out, but this is one of those "Hey, I have an idea with this!" Kind of cards, and I like those cards. I'd probably give it a 3/5.