Yorick, One with the Moon

Deathtouch, reach
Whenever another wolf enters the battlefield
under your control, target creature gets +1/+1
and trample until end of turn.
Whenever another elf enters the battlefield under
your control, add {g} to your manapool.
As long as you control 5 wolves, elves you control
have haste and lifelink.
As long as you control 5 elves, wolves you control
have vigilance and it's always night.