How to Get Skulls Livery for Mammoth Avenger in GTA Online?

The Mammoth Avenger in GTA Online has around forty different liveries, but some of them are quite rare. One of these is the Skulls livery, which was only available during special events:

• April 18–24, 2019 — unlocked by logging into the game;
• October 2025, as part of the Vinewood Undead Collection — rewarded for completing Weekly Challenges during the first three weeks of the Halloween (38/2025, 39/2025, 40/2025).

You can apply this livery at either of the two places where the flying fortress can be modified — Hangars and Facilities.