Mercule
Adventurer
Because elf-ladies are sexy-hot model babes and bloated spider things aren't. It's trite and cynical, but the simplest answer.No matter which way I look at it, I just can't see a reason the designers chose to make becoming the image of your god a punishment.
IRL, many, many slurs become badges of pride. Not all, but a very good number. A valid result of Lolth's curse could be that even her attempts at venerating her new form are tainted. She may have tried to turn it into a reward, but can't get past it sterilizing the recipients, as well as removing their ability to work magic and giving them a bit of brain damage.because lolths form is a curse from corellon which she can't break
Either way, the "correct" answer, per implied setting (and Greyhawk/FR) to the original question would be "They don't. Ever." Those in charge of the ceremony wouldn't do it. You might as well ask what would happen if a Catholic priest baptized a dead iguana or a Rabbi conducted a Bar Mitzvah for a pig. The questions themselves are almost offensive to anyone in a position to act on them.
Should an outsider somehow get the ceremonial instructions and perform them, the answer takes one of three forms:
1) Lolth withholds her power. Nothing happens.
2) Everyone dies. Lolth's direct intervention is required for the ritual to work, so you're pretty much screwed.
3) The targets of the ritual become giant spiders, complete with the brains of giant spiders. No save is permitted. The effect is instantaneous, not permanent, so it can't be dispelled. Likewise, remove curse is no more effective than it would be on a drider. As a bonus, no form of resurrection or reincarnation will work because the target isn't dead. When they do die, these spells work as they would on a "normal" giant spider. Don't screw with Lolth.
Whatever you do in your home campaign is up to you. The above is what I see as being viable based on my understanding of canon.