What happens if you don't drink water for 3 days?

Surprisingly enough, you:
Gain water weight, 
Lose focus,
Your energy levels drop, 
You can get crankier,
Your risk for a stroke becomes higher, 
You feel hungrier, 
Your metabolism becomes slower, 
You may get headaches, 
Your skin worsens (acne, dry skin, etc),
Your workout performance suffers, 
You stop crying, 
(For men) Occasionally there are cases of erectile dysfunction,
Your pee changes color,
You have trouble going to the bathroom, 
Your kidneys will tank, 
And your heart will tank as well. 

Mri or anything that has uv lights