Skell, The Retired King

All other Skeletons get +1/+1
When Skell, The Retired King enters the
battlefield create 4, 1/1 Black Skeleton tokens
Whenever 4 or more Skeletons attack they
get +1/+0 until end of turn
Whenever 4 or more Skeletons die during
a turn, return 2 Skeletons from your graveyard
put 1 in your hand and another in play