Aether Walker

Sunburst. (This creature enters the battlefield
with a +1/+1 counter on it for each color of
mana spent to cast it.) When Aether Walker
enters the battlefield search your library for all
Sigil spells and exile them. You may cast Sigil
spells exiled this way that match the color mana
used to pay this creatures casting cost.
{t}: Add {w}, {u}, {b}, {r}, or {g}. You may cast
a spell encoded on this creature.
Once slain by merciless eternals, rumor's grow of
familiar forms being seen.