@Override
public Item getItemDropped(int p_149650_1_, Random p_149650_2_, int p_149650_3_) {
	ItemStack DenseIronSword = new ItemStack(SwordModMain.DenseIronSword);
    DenseIronSword.addEnchantment(Enchantment.sharpness, 3);
    
    worldObj.spawnEntityInWorld(DenseIronSword)
	return null;
}

 

 

You can't convert an

ItemStack

to an

Entity

as they're completely separate types. You can create an

EntityItem

from an

ItemStack

, but that's not what you should be doing here.

 

Block#getItemDropped

is meant to return the

Item

dropped by the

Block

, not spawn an

EntityItem

in the world. If you need to drop an

ItemStack

with NBT (e.g. enchantments) or drop multiple types of item, override

Block#getDrops

to return a

List<ItemStack>

containing the

ItemStack

s you want to drop.

Thank you