When Form of the Mulldrifter enters, draw two cards.
You may
castTo cast a spell is to take it from the zone it’s in (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. A player may cast a spell if they have priority. See rule 601, “Casting Spells.”
To cast a card is to cast it as a spell. (CR 701.5) creature cards from your hand as though they were the card Mulldrifter. (You can still
evokeEvoke represents two abilities: a static ability that functions in any zone from which the card with evoke can be cast and a triggered ability that functions on the battlefield. “Evoke [cost]” means “You may cast this card by paying [cost] rather than paying its mana cost” and “When this permanent enters, if its evoke cost was paid, its controller sacrifices it.” Casting a spell for its evoke cost follows the rules for paying alternative costs in rules 601.2b and 601.2f–h. (CR 702.74) this way. They're Mulldrifters.)