This creature attacks each combat if able.

This creature can't be blocked by Walls.

You may have Rhox assign its combat damage as though it weren't blocked.

: Regenerate Rhox. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Flying (This creature can't be blocked except by creatures with flying or reach.)

: Shivan Hellkite deals 1 damage to any target.

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

At the beginning of your upkeep, return a green creature you control to its owner's hand.