This is my Idea.
A storm event with a medallion dropped by any mob in the event in Super Hard mode its the same as a solar eclipse and a blood moon but those are hard mode and super hard mode.
2% chance of happening every morning any biome.
Enemies:
-Thunder nimbus, hits you with rain and thunderbolts
-Walking shark, unicorn/fighter AI which has a ton of attack
-Water Elemental, a stronger ice elemental and can teeport like a chaos elemental.
If you are in an Ocean biome and a storm is happening the enemies are:
-Mini Boss King Jelly
-Baby Fishron, like a duke fishron but easier to kill and smaller
-Sand Thing, a stronger Swamp thing
Items:
Storm Medallion, Calls forth a storm
Thunder cloud, Fuse with a nimbus rod and 25 souls of storm
Soul of storm, "The Essence of Thunderbolts"
Shark sword, rare drop from walking sharks
Jelly Staff, Summons a mini King Jelly
Electro Drill, Very fast drill faster than acceleration drill but less pickaxe power
Shark Cannon, Uses shark fins for ammo
Water Orb, Material fuse with magmafrost bolt 20 nanites and 40 souls of storm = Omega bolt
Might be more items...
Well that's it I Don't Really mind what you say i just think it's a good idea.