The Halloween Grenade is a special gadget that was available during the Halloween Update 2013 and 2014. They costed 750 
and when thrown, takes 2 seconds to detonate, a flare marking it's location before detonating and marking the location of any player caught in the blast, assuming they survived. Since the update, they have been removed from the store but are still usable if you had purchased and kept them before the update. Though the Grenade Fest Update has brought these wonder grenades back into respawnables.
The Halloween grenade
Advantages over Frag
It has a Flare to signify where it is going. The radius is slightly bigger, allowing more hits and tags victims with bats, easily tracking down camo in Snow Village.
Disadvantages
Along with normal frag problems, some people may find the smaller fuse debilitating. It has 75% damage of the frag, and can be useless unless flanking or trapping someone with barrels. Anyone with at least 2 speed can dodge the bomb without trouble. It takes longer to reload, and the flare can give away the position. Whether you want this, the frag, or something else is a matter of personal preference.
Gallery
Respawnables - Halloween Grenades
Trivia
- It returned on the Grenade Fest Update, which can be won on the Hand Grenade Fest and returned again on the recent Halloween Update 2014, which can also be won on the Monster Mash or bought in the shop.