Answer:
A natural tattoo on babies
I have joy in bringing two together, but darning my existence! My life hangs by a thread, filled with ups, downs and resistance!
I look at you, you look at me, I raise my right, you raise your left
You'll have to consult an optometrist if you want to improve this.
They are toothy nocturnal immortals.
I touch the Earth, I touch the sky, but if I touch you, you’ll likely die. What am I?
Easy
Animal
Difficult
Food
Funny
Kids
Logic
What am I?