Unkillable imps in Hell to Pay. WTF?

I'm playing Hell to Pay for the first time and it's not bad at all. So I get to level 14 and what do I find? The modified imps which I've been happily blasting away previously now have a ghostly cousin. These partially invisible imps pass through all walls and doors and seem impervious to all weapons, perhaps even the BFG, although I haven't acquired that yet. How in the name of all that's holy are you supposed to fight them?

Actually I've run across this before. I can't recall which megawad but on one level there were ghostly stormtroopers who pursued you the whole damn time through all obstacles and were equally unstoppable. I had to switch into God mode to get through that time and I think I abandoned the megawad in disgust at such unsportsmanlike modding.

So, has anybody run into this? Is there a way of dealing with them that I'm missing or are you seriously expected to get through the map with these infuriating spawn of a demented mind at your heels?

Those are ghost monsters. They can only be damaged by melee attack from another monster (not your melee attacks, though) or by the blast radius of an explosion. Use your rocket launcher.

Them being translucent means that you are using ZDoom or GZDoom. It's a little addition that tells you they are ghosts; in other ports they would be indistinguishable visually from their normal brethren.

I had my first encounter with these fellows in "Icarus". However, different from H2P, they explained there what to do with a screen you see at the beginning of the level (rocket launcher close to the "ghost").
There are not too many maps which use this feature, but it's always something special when it happens. And you pray that you have spare rockets... ^^

I remember bitching at the ghost monster bug being fixed, and being told it wouldnt ever be unfixed. Now look at those ports :p

Many thanks, guys. Rocket splash damage does indeed do the trick, although it's damnably difficult to pull off without mortally wounding oneself into the bargain. Still, these things are sent to try us and at least I now know what's going on and how to fight it.

NightFright said:

There are not too many maps which use this feature

In this post, I gave a list of levels (edit: that I knew of as of 2006) where the AV/ghost bug is used deliberately, along with some other info and links.

gather2 map05
wtrfront
archie
seej
icarus map24
6pack map02 [in 6pack2.zip on the archive]
squadron map21
eternal map25
requiem map23
hell2pay map14
hr map26
av map19

You can add PL2 MAP32 to your list. For whatever god awful reason, there's a room near the end with an archvile hidden in a waterfall who resurrects SS Nazis who teleport under a crusher...

reverie map18 too, there's a bunch of imps crushed and resurrected after which they chase you around a "haunted mansion".

quasar: those would be a homage to the requiem ghost nazis.