The Grim Reaper is the NPC that would give you an extremely powerful ship called the Grim for completing the quest that he gave; Death Incarnate. The quest required 100 Space Pumpkins and 5 Ghost Pumpkins.
The Grim Reaper is located in the Halloween Mega Base in the pumpkin field.
Quest Dialog 1
Grim Reaper: Hey, want to do me a favor?
Player: What is the favor?
Grim Reaper: I noticed that the king reached his final form of evolution
Player: Go on.
Grim Reaper: I want you to defeat the king and loot everything he drops.
Player: What do i need to get from him?
Grim Reaper: You will need to get me 5 Ghost Pumpkins and 100 Space Pumpkins
Player: What will my reward be?
Grim Reaper: If you get me those, I will give you my true ship
Player: I'll do it
Grim Reaper: Good, be careful, because he is quite powerful right now.
Player obtains quest: Death Incarnate
Completing the Quest (continued)
The player then needs to obtain 5 Ghost Pumpkins and 100 Space Pumpkins by defeating a stage 3 Harvest King. This can be extremely difficult as the Harvest King can take on multiple Dreadnoughts if distractions such as the Draco and Viper are not present. Once destroyed there will probably be many vultures, so stay alert. Each stage 3 Harvest King drops 1 Ghost Pumpkin and 25 Space Pumpkins. Since a Harvest King only spawns once per round, the player must hop servers if they wish to continue. After obtaining the requirements the player must head back to the Grim Reaper to turn in the pumpkins for their prize.
Quest Dialog 2
Grim Reaper: You got all the pumpkins?
Player: I got all the pumpkins
Grim Reaper: ...
The quest has now been completed, the player is awarded the Grim.