The remotely triggered Castanas quietly deliver a lethal dose of electricity to unsuspecting enemies.
The Castanas are a throwing type secondary weapons with an electrical detonation charge that can be detonated remotely by using the zoom command, much like the Penta. Although lacking in throwing speed like other thrown weapons, they can be stacked up to 6 then detonated all at once to create a wide array of crowd controlling opportunities thanks to their electrical explosion and chaining effects.
Has base damage type of Electricity, allowing Castanas to easily be modified to Radiation damage for Heavy Grineer units, Corrosive damage for Ancient Infested units and Magnetic damage for Corpus units.
When Magnum Force is added, the Castanas will begin to spread apart on throws if Multishot mods are applied. This may be helpful for combating the small blast radius they have by spacing them slightly apart from each other.
Throwing these at an Arctic Eximus snowglobe and detonating them will kill the Eximus.
Castanas uses the pistol ammo mutation mod not sniper ammo mutation, while still using sniper ammo.
Castanas thrown by Mirage's illusions from Hall of Mirrors will not interfere with the maximum amount of armed Castanas at a given time.
Caution should be taken when this weapon possesses elemental damages such as Magnetic, Toxin and Viral, as these would deliver their corresponding negative effects should the user be caught in the blast area.
As a Nyx, throwing several Castanas to the floor, casting Absorb on top of them and detonating them makes a good (and fast) combo for an instant "charging" Absorb with the right build.
Mirage'sHall of Mirrors can be used to increase number of Castanas that can be planted, but the holograms' Castanas will detonate a few seconds after impact; though they will not damage the player and can still also be detonated manually.
If you are willing to take the damage, you can detonate the Castanas right on top of yourself by pressing the fire and zoom keys at the same time. This technique is useful for Link + Blessing Combo.
Note that as of Update 13.3, the Link+Blessing Combo is less effective, due to the fact that Blessing doesn't confer invulnerability any longer.
Although the Castanas use Sniper Ammo, they are a secondary weapon, which disallows the use of the Sniper Ammo Mutation mod and instead uses the Pistol Ammo Mutation mod, which strangely still functions properly.
Due to the Castanas' nature of using sniper ammo since their ammo capacity was fixed, they will alter the ammo capacity of primary weapons that utilize sniper ammo.
Equipping the Castanas with any sniper or bow weapon will decrease their overall ammo capacity.
Equipping the Castanas with the Ogris, Torid, or Penta will increase their overall ammo capacity.