$0.29 @ TCGplayer
Choose any number of target players or planeswalkers. For each of them, reveal cards from the top of your library until you reveal a nonland card, Kaboom! deals damage equal to that card's mana value to that player or planeswalker, then you put the revealed cards on the bottom of your library in any order.
As Kaboom! resolves, you choose one of the target players or planeswalkers before revealing any cards, then complete the spell's process for that player or planeswalker, and then repeat until each target has been through the process.
If all the cards in your library are lands, this card deals zero damage.
