{T}, Sacrifice Mimic: Add one mana of any color.
{2}: Mimic becomes a Shapeshifter artifact creature with base power and toughness 3/3 until end of turn.
If an effect refers to a Treasure, it means any Treasure artifact, not just a Treasure artifact token.
Mimic is still a Treasure after its last ability resolves, but Treasure is an artifact type, never a creature type.