Sebastian considers this design to be of great personal significance. It represents his extensive experience with sharks and diving as well as a breakthrough in the realm of relief carving 'with a design that perfectly encompasses the features of the shell'. Further to this Sebastian has said, "It accurately depicts the first person standoff between a man and an apex predator, quite an experience I can assure you".

"This is the designs from Bidjidanga or Roebuck bay." This would make it either Karrajari or Yawru. He believes it is one of the famous marks of the saltwater people from around Broome.

This Riji is one of the traded design group. Although the design is not provenanced, this shell carries the characteristic interlocking key motif, in this case, expressed as an open design forming a maze. The pattern begins to bend with the shape of the shell, creating the subtle movement that is distinctive of geometric shell art.

Sebastian is from the Yawuru language group near Broome, Western Australia. He has lived in this area for most of his life. The well known senior law man and artist Aubrey Tigan has become his mentor and is teaching him the traditional designs and craft of this area. Sebastian is now able to produce some of the old local law designs and tarding designs that Aubrey has been making in his extraordinary artwork on pearlshell. Riji are carved pearlshell, rubbed with ochre. They were traditionally used as a trading device with in land tribes and during men's initiation ceremonies.