A butterfly，depends on how you interpret it whenever you see a real one.
1.Death → for some a butterfly means death as its life is very short 2–3 days.
2.Freedom → after being in incubation for a long time, they get free and beautiful.
3.Hope → after a period of suffering, something good will eventually happen.
The ? sign also means your telling someone that they're attractive. It can also mean that your in a positive mood. Other meanings to it are nature related and showing the idea that your in love with the expression, ‘I have butterflies on my stomach.