Baffling End

When this enchantment enters, exile target creature an opponent controls with mana value 3 or less.
When this enchantment leaves the battlefield, target opponent creates a 3/3 green Dinosaur creature token with trample.

The List

Rivals of Ixalan

When Baffling End enters the battlefield, exile target creature an opponent controls with converted mana cost 3 or less.
When Baffling End leaves the battlefield, target opponent creates a 3/3 green Dinosaur creature token with trample.

In a multiplayer game, the target opponent who creates a Dinosaur token doesn’t have to be the same one whose creature was exiled.

While Baffling End’s two abilities are flavorfully related, they are independent. If the first ability doesn’t resolve (perhaps because the target gained hexproof), the second will still create a Dinosaur token when Baffling End leaves the battlefield.

"Dinosaurs pick up scents from miles away. We're here to observe and document, not interact."
—Sarah Harding

Dinosaur

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)