History of Basilisk

Overview

Basilisk is a Legendary weapon: Shotgun (Rapid-Fire Frame), Arc, 140 RPM.

Curated roll per the fan wiki: Smoothbore, Auto-Loading Holster. Introduced in Season 3 (Warmind-era). Magazine size differs between sources (7 vs 8), likely roll or version differences.

Acquisition

Earn rank-up packages from Arach Jalaal, the Dead Orbit vendor.

This is a legacy-style reward weapon. It is not a craftable or Adept weapon as far as the sources show, and sunset status was not stated by the sources I opened (the fan wiki is the main source). See also Arach Jalaal and the Crucible for the PvP context.