Blast o' Lantern

Blast o' Lantern is a throwable item obtained from killing Wither Gourd during Spooky Festival, but they can also be crafted. This can be used as an easy method for newer players to gain Slayer XP by throwing a single Lantern at Revenant Horror, assuming one can obtain them in the first place. They can also be used to create Pumpkin Launcher which also uses the Lanterns as ammo.

Obtaining
Wither Gourds drop on death, but they can also be crafted.

Uses
Combat as well as crafting the Pumpkin Launcher