What is Thunder Strike?
When exploring the different locations provided by the Stalwart Dungeons mod, you might obtain an Enchanted Book, which is Thunder Strike. There are three levels to this Enchantment. It can cause weapons to summon a bolt of lightning.

The Thunder Strike Enchantment should be applied to a Hammer, a new weapon added by Stalwart Dungeons. When applied, you can sneak and left-click a target, and a lightning bolt will strike them.
It can only be applied to Hammers, and you’ll need to be close to a target for it to work. So with that said, it’s likely that you will also be struck by lightning. You might find it helpful in some situations, like creating Charged Creepers.
Crafting Hammers
There are eight different tiers of Hammers available. These are melee weapons but can also be used to break blocks. Hammers can be made from Wood, Stone, Iron, Gold, Diamond, and Netherite. But there is also the Tungsten Hammer and the Nether Hammer.

Even though Hammers can break blocks, they’re slow. Though if you use the Nether Hammer (not the Netherite Hammer), it can smelt items as they are mined. If you have the Thunder Strike Enchantment in Book form, then apply it in an Anvil.