The Legion Basilisk was a common variant of the standard Imperial Army Basilisk Self-Propelled Artillery Tank that was used by the Space Marine Legions during the Great Crusade and Horus Heresy eras of the late 30th and early 31st Millennia. The long-range Basilisk, Medusa Siege Tank, and the Deimos Whirlwind were some of the most common artillery units deployed by the Legiones Astartes.
In the late 41st Millennium the various Chapters of the Adeptus Astartes no longer make use of long-range artillery tanks, instead using the Whirlwind Multiple Missile Tank almost exclusively as their ranged artillery support.