Hexproof, indestructible

Shadow of Vorthos can't attack.

At the beginning of your upkeep, put a -1/-1 counter on Shadow of Vorthos, then if Shadow of Vorthos has 10 or more -1/-1 counter on it sacrifice it and you may cast your commander without paying its mana cost if your commander is "Vorthos, Shapeshifter".

Whenever a player cast a spell, before the spell resolves Shadow of Vorthos phases out, it phases in after the spell leaves the stack.