What Am I Riddles

Question: I live in the dark, I have no heart and I'm just like jelly, if you touch me I'll stung you. What am I

Question: I'm the son of water, but when I return to water, I die. Who am I?

Question: I live with first ones ,they use me well! For the others I am hell! For the third ones I am useless,you can't touch me but you can see me! I am always there within you! Seek for me and and I'm right there! What am I?

Question: Skinny I am fast,
fat I am slow,
but I'll still delight you from your eyes to your nose.

What am I?

Question: Feathers, I am as light,
But quite heavy if squeezed tight.
I'm seen as clean and pure,
but often talked about with dirty terms.
What am I?