The Monster Pack Add-on for LEGO Worlds has 5 achievements.
Collect Vampire & Vampire Bride, then place them together in the Monsters castle
Use the paintball gun to splatter paint on all the new monster characters
Stake a claim to Monster Town by playing as the classic Vampire character in the Monsters pack
Create a single custom character, using a part from each of the new monster characters
Play a guitar solo in the Monster Biome stage area in front of the crowd