Back during the 2018 Halloween Event, this rare gun was handed out to anyone who reached the 22nd tier of the Main Event — that's the only way it ever entered the game, and that door closed when the event ended. It's a Halloween-themed gun, so the people who chase it are usually collectors finishing event sets or just fans of the spooky look. If you want it now, you have to find an owner willing to part with it.
Vampire (2018) is a Rare gun in Murder Mystery 2. Its combined value is 6.5, #23 of 146 rare items and #387 of 921 valued items overall. Demand is low: it sits in inventories for a while, and buyers often ask for a discount.
Closest in value: Shadow (6.5), Toxic (2018) (6.5), Aurora (2019) (7). Use them as a benchmark for a fair one-for-one trade.
Value history
What it is worth in other items
1×Shadow
1×Toxic (2018)
1 : 1.1Aurora (2019)
1 : 1.1Broken
1 : 1.1Frostbite
1 : 1.1Heart Pet
1 : 1.1Ice Dragon
1.1×FlamesHow many of each item equal one Vampire (2018) by value. Demand differs between items, so check it before you trade.