The Inkras Butterfly is an agent for both Creatures 3 and Docking Station.
They are classified as a bug and can be found on TwilightCat's page and also on CreaturesFrance and also at Eemfoo.org. They are perfectly safe to eat (highly recommended for Draconian Norns) and can be very beautiful fluttering about in your world.
In Docking Station, injecting this agent will create four of these butterflies in the upper level of the Norn Meso. It is highly recommended that you have plenty of plants available and growing, otherwise the caterpillars will have nothing to eat and won't change into more butterflies. If the number of butterflies drops below four, they will be recreated in the Meso.
Here is the description from TwilightCat's page: "These happy little butterflies have found their way through a portal from Bug's world. Now they flutter about teasing the norns. You should have some plants installed for their caterpillars to eat. Like the Cheese Plant or any other plant you know of..."
See also the Okiron Butterflies and the Lensis Butterflies.