Rebounding Passageway

creatures with Phasing gain Lifelink
all Highborn gain Phoenix as a subtype
at the start of your upkeep gain one mana(color
of your choice) for each other shrine you control
(these are not permanents) you may sacrifice X
number of lands to summon X phoenix
from your graveyard
what is this place...
a door to eturnity i know what i must do....