Supply Caravan

When this creature enters, if you control a tapped creature, create a 1/1 white Warrior creature token with vigilance.

Amonkhet Remastered

When Supply Caravan enters the battlefield, if you control a tapped creature, create a 1/1 white Warrior creature token with vigilance.

"We each have a weight to carry on the road to the afterlife."
—Oketra, god of solidarity

Amonkhet

If an effect causes Supply Caravan to enter the battlefield tapped, it will satisfy its own triggered ability.

If you don’t control a tapped creature as Supply Caravan enters the battlefield, its ability doesn’t trigger, even if you can tap a creature right away. If you control no tapped creatures as the ability resolves, nothing happens.