Helm Greycastle

First Strike, Haste, Mentor
Whenever a Knight attacks, you may have its controller create a 2/2 white Knight creature
token with vigilance that's tapped and attacking.
{r}{r}{r/w}{w}{w}: Untap all attacking knights. White creatures you control gain lifelink, and red
creatures you control gain flying. After this
phase, there is an additional combat phase.
Activate this ability only once per turn.