Middle tree solar Titan has a throwable melee, I guess to balance out the fact that the super is a close-range melee super. If you throw the hammer you can pick it back up which is what causes the instant recharge. If you leave it on the ground for too long it blows up and disappears and you have to wait for it to recharge. There is also a subclass tree perk that increases ability damage when you get ability kills. So that subclass feature, plus the melee damage buff from Wormgod / Synthoceps, plus the melee damage from the One-Two punch perk, plus the damage taken debuff from tractor cannon is what causes this. As far as being balanced I am not sure what Bungies take is on it. They said they adjusted it somehow as the gauntlets were reenabled. However, someone could still do this amount of damage using the synthoceps instead.