Midnight blue shubunkins (sometimes called midnight shubunkins) are very rare. Only one commercial breeder worldwide, usually only 20,000-40,000 for sale each year. I have over 15, bought most directly from the breeder (1 hr roadtrip).
A mbs has sky blue, white and black, alot have a cream colored head, no orange or red. The black is permanent, unlike most comet babies that have black/dark brown the first year or so.
Shubunkins are multi-colored, alot have some steel blue, orange, black, red (not so much white.
Left of pic, 3rd fish down is a midnight blue shubunkin. So, is large fish in center, but not a great color scheme.