Players can spawn the Cursed Storm in Fisch by using the Aurora Totem or Cursed Storm Totem. Then fish in the Pool for an 8% chance to catch fish with the Cursed Mutation.
To get the D.R.E.D Rod, you must complete a task that involves catching Cursed Fish. Many people assume this is from the exclusive FischFright 3 Pool. However, that's not the case; it is linked to the Cultist Curse Fishpool and requires you to trigger the Cursed Storm. So, if you are confused like me and wondering how to finish this task, here is a detailed guide.
How to Spawn the Cursed Storm in Fisch
As mentioned earlier, you must catch Cursed Fish as part of the D.R.E.D Rod quest. Specifically, you need to catch 9 Cursed Fish. For this, you have to spawn the Cursed Storm. You can spawn the Cursed Storm in two ways: the Fisch: Aurora Totem or the Cursed Storm Totem.

Every time you activate an Aurora Totem, there is a 20% chance at the start of the Aurora Borealis to spawn a Cursed Storm. You can easily obtain Aurora from chests or the Daily Shop for 400,000C$. Alternatively, you can use a Cursed Storm Totem for a 100% chance to spawn the event; you can buy it from the Rare Goods Dealer for 50C$ or from the Daily Shop for 600,000C$.
Also, when the Cursed Storm appears, it usually spawns at the Grand Reef. So, hop on the boat and go to the POI to start fishing inside the Pool.
How to get the Cursed Mutation in Fisch

The Cursed is a unique Mutation in Fisch and isn't available through any rod or enchantment. Instead, you can get it only through the Cursed Storm Pool. Spawn a Cursed Storm using an Aurora Totem or Cursed Storm Totem, then fish in the Pool for an 8% chance to catch a Cursed mutated fish. You can also get Cursed Fish during the Pond Emperor Uprising Event (10% chance). However, this is very random, as it is an admin-only event that spawns randomly during weekend Admin Abuses before updates.
For more on Fisch, check out How to get the Oppressor & Black Fairy Rod in Fisch or All 29 Fish in the Skycrest (100% Bestiary) - Fisch