A manrope knot (double crown and wall) is usually not found on a DS.
Image from Wikimedia
But it makes a good toggle for a rope shackle (a short length of line where one end is an eye splice and the other end is a bulky knot).
Each strand is tucked first under the next neighbor, then under again, but pointing down, rather than up. Then the strands are doubled for extra bulk, by taking the end of each strand and following the strand one more time through the knot.
That repetitive process works well with ropes that have more strands, such as 12-strand Amsteel. (Just don't try to work with all 12 strands, use them in pairs or triplets.)
Basic instructions here.