WhatsApp Puzzle: I am a 8 Letter Word

Whatsapp Puzzle: One more Whatsapp puzzle for you to crack. I am a 8 Letter Word. I am kept Secret from Everyone. My 2nd, 3rd, 4th Letter Spell an Animal. My 4th, 5th, 6th, 7th, 8th Letter is a Weapon. My 1st, 2nd, 8th Letter is used for Writing an Exam. My 3rd, 4th Letters