Hey everyone, I'm in this game as well so I appreciate all the replies/advice so far. Just to clarify though- I am NOT the harpoon wielding character. I just want to make the game fair for all of us players. I'd like to find a way for my friend to use his "harpoon build" that doesn't- 1) over-shadow the rest of us, 2) force the DM to use too powerful monsters that can withstand his attacks but will be too much for the rest of us to handle and 3) still lets the Harpooner use his character without feeling like he's been completely nerfed.
XCorvis said:
On the second round, did he do the same amount of damage he made with the Powerful Charge/PA/Blades of Blood? It might be RAW, but that's something I'd house rule out. Removing the harpoon should do base harpoon damage, maybe plus strength, but shouldn't let you get double the effect for the spells and feats you used last round.
Until we paused the game to discuss how broken this use of the harpoon is, yes he was doing all the damage from the first attack. But we fixed that- Blades of Blood gets discharged with the first attack and you can't PA/Powerful Charge on a Heal check (which, by RAW, is what removing the harpoon is). I'm also thinking that the damage from Blades of Blood shouldn't count on the reflex save to avoid getting the harpoon stuck.
As was mentioned in the OP and later, the closest analogy for using the harpoon in melee is the javelin. But while the javelin specifically says it is "not designed for melee" and imposes a -4 to hit as a melee weapon, the harpoon doesn't have that exception. It's whole description does deal solely with ranged attacks though, so adding the same rule as the javelin seems pretty reasonable.
Nail brings up a good point about using the harpoon in melee not matching it's ranged use description so the "lodging" effect wouldn't apply. But, while that's a valid RAW way of avoiding the issue, it doesn't make much logical sense. Stabbing two-handed with a harpoon in melee (regardless of a -4 penalty to hit) will certainly hit harder than throwing it one-handed, which is why the 150% damage for two-handed weapons would apply. So how could a harder hit with a harpoon not lodge while a ranged hit would? It makes a lot more sense to simply say a hit is a hit and the lodging effect applies regardless (no matter how complicated that makes adjudicating the rest of the weapon's effects

)
So here's a proposal of how to deal with using a harpoon as a melee weapon:
1) It's not designed for melee so it imposes a -4 penalty to hit
2) If it deals damage there's a chance it is lodged in the target- reflex save DC10 + harpoon damage (BoB doesn't could but PA & PC would) to avoid.
3) Once lodged there is an opposed strength check to keep control of it. If the wielder is trying to keep control of the weapon then he doesn't threaten since his weapon is occupied, unless he has Quick Draw and another weapon (or something similar) and opts to let go of the harpoon to make an AoO.
4) If you loose control of the harpoon (whether by failing the STR check of voluntarily letting go for some reason) you can try to grab it again- this would be resolved as a disarm attempt.
5) If you have control of a lodged harpoon you can take a full round action to rip it out. This is a full round attack and does not provoke AoO. (The RAW say it's a Heal check but that's to remove it without doing extra damage, if you don't care about that then it should still be a full round action but not one that distracts you enough for AoO) Ripping a harpoon out like this does damage equal to the original attack but for the weapon + STR only. (No PA/PC or extra spell effects)
There- how does that sound? At least it's simpler than grappling.

But seriously, I think that covers most of the differences from ranged use to melee use. And it's not completely devastating to the target of the attack. But does it make the harpoon fair to use? Or is it broken beyond repair even before this patch?