Crabs are awfully romantic
Nature never ceases to amaze me!
For most crab species, the female can only reproduce after she has freshly molted, which allows the male to deposit his spermatophores. A male crab will seek out a female who he knows is about about molt and embrace her for days, sometimes even weeks. After she finally "strips down" in his arms, they reproduce and the male may continue to "hug" the female for days after copulation to protect her until her new shell hardens.
I'm sure there's a life lesson in all this.
Ned and Anna Deloach of blennywathcher.com shot a cool video of a pair of box crabs mating.