When this creature enters, tap target creature an opponent controls.
Doors, walls, skulls . . . it matters not. All barriers will be broken.
Illustrated by David Gaillet · Magic Origins · #18
There are no rulings for Heavy Infantry.
Rally — Whenever this creature or another Ally you control enters, tap target creature an opponent controls.
When this creature enters, destroy target artifact or enchantment an opponent controls.
When this creature enters, you become the monarch.
When this creature enters, exile target creature an opponent controls until an opponent becomes the monarch.
Landfall — Whenever a land you control enters, tap target creature an opponent controls.
Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Whenever this creature attacks, tap target creature an opponent controls.