After viewing the “Rage of the Spanish Inquisition” comic here: http://www.facepunch.com/showthread.php?goto=newpost&t=821191

I felt it would be rediculously awesome to have a Spear-RPG SWEP.

As in, throw an RPG like it’s a spear, it impales the target, then it EXPLODES.

There s a Rocket Propelled Chainsaw swep,want a link? http://www.garrysmod.org/downloads/?a=view&id=38121

Well you could make an entity with the RPG model, make it without collide type and parent it to a Harpoon, It should stick to walls and pierce through NPCs. Then just make it go boom.