Boomstacker

As this creature enters and whenever it attacks, stack two dice on top of it. (All dice must be stacked vertically, one on top of another.) This creature gets +1/+1 for each die in its stack. This creature attacks each combat if able. When the stack falls, sacrifice this creature.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6oe5cva06vpb1hm6cct7te.