Chameleons

noun

1. A small to mid-size reptile, of the family Chamaeleonidae, and one of the best known lizard families able to change color and project its long tongue.
2. A person with inconstant behavior; one able to quickly adjust to new circumstances.
3. A hypothetical scalar particle with a non-linear self-interaction, giving it an effective mass that depends on its environment: the presence of other fields.