Door to Anywhere

During your end step, place a counter on Door
to Anywhere.
At the beginning of each upkeep phase, that
player will Siphon X (To siphon X, target player
exiles the top X cards of their graveyard, then places
the top X cards of their library into their graveyard.
X equals the number of counters on this card.)
{2}: Remove a counter from this card. Any player
may use this ability.