Bolas' Palace

Bolas' Palace enters the battlefield tapped unless
you control a Bolas planeswalker or a planeswalker
an opponent controls left the battlefield this turn.
{t}: Add {u}, {b}, or {r}.
{u}{b}{r}, {t}: Amass 2.
"Well, let's see here, my lord... yes, this supposed
Wanderer was quite elusive... she will be converted as
well, of course..."