Answer:
Tear me off and scratch my head what once red is now black.
I am a type of weapon for SCI-FI characters
Everyone in the world needs me. They generously give me but never take me. What am I?
Squeeze me and I cry tears as red as my flesh, but my heart is made of stone. What am I?
What is easy to get into but hard to get out of?
Who makes it, has no need of it. Who buys it, has no use for it. Who uses it, can't see it. What is it?