Black Witch's Jet Amulet

Black Witch's Jet Amulet enters the battlefield
tapped.
{t}: Add {b}.
Rainbow: (As long as one mono-color permanent of
each color is in play, the game has rainbow) Sacrifice
Black Witch's Jet Amulet: You may search your
library for an Curse; or Pay 3 Life to search for
an Enchantment or Black card. Reveal that card,
shuffle your library, put the card on top of it.
"It silently echoes a thousand words of lingering
malice."