Create a random file on linux using dd and /dev/random

I executed this:

$ dd if=/dev/random of=foo bs=1G count=1
0+1 records in
0+1 records out
6 bytes (6 B) copied, 0.00016958 s, 35.4 kB/s

$ stat -c "%s" foo
6

Also this does not work, I get stuck in the command:

$ head -c 500 /dev/random > foo

What is my mistake?

I'm on Linux mint.