Examples:

• I've never seen that before in my life.
• This is not my bag, and I've never seen that before!
• Sunny's case is so strange, I've never seen that before.
• I've never seen that before in my life.
• I know. I've never seen that before in my life.
• I've never seen that before— the lining.
• No, I've never seen that before in my life!
• That's not mine. I've never seen that before in my life.