Flying
When Halo Forager enters, you may pay . When you do, you may cast target instant or sorcery card with mana value X from a graveyard without paying its mana cost. If that spell would be put into a graveyard, exile it instead.
You choose whether or not to cast the target instant or sorcery card as the reflexive triggered ability resolves. If you do, you do so as part of the resolution of the triggered ability. You can't wait to cast it later in the turn. Timing restrictions based on the card's type are ignored.
14-04-2023
wotc
Halo Forager's enters-the-battlefield ability triggers and goes on the stack without a target. If you pay {X}, the second "reflexive" triggered ability will trigger. You'll choose the target instant or sorcery card for that second ability at that time, based on the value you chose for X. X can be 0.
14-04-2023
wotc
If the card has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
14-04-2023
wotc
If you cast a card "without paying its mana cost," you can't pay any alternative costs. You can, however, pay additional costs. If the card has any mandatory additional costs, those must be paid to cast the card.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.