Biomimetic lifeform
From Memory Alpha, the free Star Trek reference
A biomimetic lifeform is an organism capable of biological mimicry, imitating other organisms or objects. The Silver Blood from the "demon class" planet classified as such an organism. (VOY: "Demon", "Course: Oblivion")
Biomimetic lifeforms may or may not include shapeshifter species such as the Founders or chameloids.
