dragons cave.

invincibility hexproof dragons cave can not be changed.
{x} +2 {t} create {x} 3/3 dragons with flying and haste
whenever a dragon dies create 1 treasure token
if dragon was a 4/4 or more create 2 treasure tokens or target creature gets -1/+2
equip legendary dragon {3}
equipped dragon gets +2/+2 and deathtouch