The Endothermic Explosive is the opposite of the Exothermic Explosive, making it generate ice rather than fire. After being detonated the explosive generates a blue laser and launches nearby blocks upward, then they spawn a huge amount of ice and water in a massive zone, around 100x100 blocks. If any mobs or players are in the blast zone they are affected by slowness 2 and a debuff added in the modpack called frostbite 2, which causes damage over time.
When fired at a forcefield it will generate a circle of ice and cause forcefield blocks to scatter around the terrain. Then it will penatrate the forcefield and cause the same effects described above, exept the ice will be in a smaller radius.