Answer:
Deposit red liquid in me.
I can be simple or I can be complex. I can be found in this riddle or in everyday life. I can be shapes or even colors.
Whoever makes it tells it not. Whoever takes it knows it not. Whoever knows it wants it not
I have roots nobody sees. I am taller than trees. Up up I go but I never grow.
If you lose me, you may cause people around you to lose me too. What am I?
Often cooked as fillet, this meat comes from an animal that swims underwater.