"Dont say that! Whenever someone says that right after surviving something dangerous, something totally random pops out and kills them!"
"I will maintain a realistic assessment of my strengths and weaknesses. Even though this takes some of the fun out of the job, at least I will never utter the line "No, This Cannot Be!! I AM INVINCIBLE!!!" (After that, death is usually instantaneous.)"
The Evil Overlord List, Rule 24

Black Knight: (After getting both his arms and one of his legs cut off] Right, I'll do you for that!
King Arthur: You'll what?
Black Knight: Come here!
King Arthur: What are you gonna do, bleed on me?
Black Knight: I'm invincible!

King Arthur: ...You're a loony.
—Monty Python and the Holy Grail
"Yes! I am invincible!"
Boris Grishenko, GoldenEye, shortly before being showered with liquid nitrogen.
"He's cut! The Russian is cut!"
Rocky IV