In order to obtain this achievement, you need two items:
- Blessed Apple: It has a 0.5% (0.67% Expert/Master) chance of being dropped by hallowed themed enemies: Chaos Elemental, Enchanted Sword, Gastropod, Illuminant Bat, Illuminant Slime, Hallowed Mimic, Light Mummy, Pigron, Pixie, Rainbow Slime, Unicorn.
- Rainbow Gun: It can be found in the Dungeon's Hallowed chest, meaning you must get a Hallowed Key first. This key has a 0.04% chance to be dropped by any creature that drops coins while in a halloweed biome. Once you get the key, you must find the Hallowed chest in the Dungeon and open it.
Once you have both items, equip the Blessed Apple, and then use the Mount key (by default R or
).