Conch shell
In short: The shell in which the hero is born in a Thai manuscript of Sang Sinchai.
Object
How does it work in the tale?
In the manuscript, Sang Sinchai is born inside the shell with an ivory bow. The unusual birth sets him apart before he begins his quest.
When does the shell introduce the hero?
The British Library’s Sang Sinchai record mentions the shell and ivory bow together at the hero’s birth. Both objects appear before the quest begins. One marks where he was born, the other what was beside him in the opening scene. Together they mark the child as extraordinary before he has accomplished anything.