Sydney Bristow [Alias]

In disguise: (has protection from, and cannot be
blocked by creatures that share the same subtypes as it)
Theft: (when this does combat damage to a player,
gain control of target artifact that player controls)
Whenever this becomes blocked, transform it.
{1}Sydney Bristows subtypes becomes that of target creature an opponent controls.
{2}Sydney Bristow transforms. Any opponent may activate this ability as if it were an instant.