Big White Dragon

Flying, vigilance, everlasting (When this creature
dies, you may exile it. If you do, create a token that is
a copy of this creature, except its base power and toughness are 1/1 and it loses its everlasting ability.)
Whenever Big White Dragon attacks or blocks,
another target creature gains everlasting.
Other creatures with everlasting and tokens you control get +2/+2.