Think of it as a reverse-Misty, in that you flip a coin until you get tails, with every heads you get removing one energy from your opponents active Pokmon
But if it can't attack an appropriate player for some reason, it could then attack a planeswalker to at least meet its must attack requirement
Karn is first mentioned in the flavor text of Fit of Rage in Weatherlight , but isnt actually seen for the first time in the first round of the supplemental Vanguard product that Wizards of the Coast released in December of 1997 shortly after Weatherlight s release
Typically, these promotions arrive at different times in different areas, rather than rolling out worldwide simultaneously
If your deck has multiple Energy Types, the generated Energy will be determined by RNG
All the enchantments can go