The act of being sarcastically friendly. A proper fusion of the words "Friendly" and "Sarcastic", relying heavily on context and is easily confused with the combination of "Friend" and "Fantastic" (Friendtastic), albeit the meaning is quite contrary. Again, look to the context of the conversation when delineating between friendtastic an friendastic.
"Oh, sure, isn't <i>that</i> just friendastic"
With a friendastic tone he said "No, I'd <i>love</i> to hear more about your poodles allergies"