die, death, dead
殁 centers on the end of life: dying, death, or being dead. The meanings are tightly clustered around the cessation of life.
殁 combines 歹 (death) with 殳, a component that may have originally depicted a weapon or action, together suggesting a violent or sudden end. The exact historical development is uncertain.
The left side 歹 is the death radical, and the right side 殳 looks like a weapon. Picture a fatal blow bringing death.
For ボツ, imagine a boat (ボート) sinking and everyone on board dying: boat -> ボツ, and the scene is one of sudden death.