Webweaver Changeling
Creature — Shapeshifter
Changeling (This card is every creature type.)
Reach
When this creature enters, if there are three or more creature cards in your graveyard, you gain 5 life.
Nicholas Gregory
Rulings
If there aren't three or more creature cards in your graveyard as Webweaver Changeling enters the battlefield, its ability doesn't trigger at all. If there aren't three or more creature cards in your graveyard as the ability resolves, you don't gain 5 life. These don't have the be same creature cards at both times.
(wotc • 2019-06-14)
Rulings
If there aren't three or more creature cards in your graveyard as Webweaver Changeling enters the battlefield, its ability doesn't trigger at all. If there aren't three or more creature cards in your graveyard as the ability resolves, you don't gain 5 life. These don't have the be same creature cards at both times.
(wotc • 2019-06-14)