I had a small vial of mercury when I was a boy. I loved playing with it. It didn’t affect my cognition, though. I was born with all the stupidity I need.
Metallic mercury is relatively safe. It’s the oxides of mercury that bind easily to cells.
L
I remember in high school lab we had Mercury and passed it to each other to roll around in our hands.
I also remember mom painting our toys. with old house paint, probably lead paint.
I think my IQ is above 80 so no problems.