Basically a big yellow bolt that charges up like a spear, except it acts as a raycast projectile with a small explosion. The damage either should be 50 or 100, with the explosion splash damage a little more than a Rocket Launcher's.
If we're gonna move on to the Quake Weapons' electric guns path, it should make a victim to be shocked, receiving crits from any source of damage. Perhaps the weapon can also deal afterburn damage, but it would be a chance.
Any concerns are acceptable about this, I might expand this request to a Mythology Weapons Pack suggestion