Ghostblade Eidolon
{2}{W}
Enchantment Creature -- Spirit
1/1
Bestow {5}{W} (If you cast ~this~ for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Double strike (~this~ deals both first-strike and regular combat damage.)
Enchanted creature gets +1/+1 and has double strike.