Flash
{T}, Sacrifice Dire Mimic: Add one mana of any color.
{3}: Dire Mimic becomes a Shapeshifter artifact creature with base power and toughness 5/5 until end of turn.
Dire Mimic is still a Treasure after its last ability resolves, but Treasure is an artifact type, never a creature type.
If an effect refers to a Treasure, it means any Treasure artifact, not just a Treasure artifact token.