red haired, horned, pale green caterpillar

[Blocked Image: https://m.ak.fbcdn.net/sphotos-d.ak/hphotos-ak-prn2/q71/1146731_415345525240568_1503059743_n.jpg]
help!! someone here!! please help me!
i found it on front of my door,, can someone tell me who is it?? and what it's food Please
and it's in L4/L5 i think
Please help me,
Thanks+ best,
Elfin