Continuing on with trying to fill in item descriptions, the Potion of Hiding and the Potion of Sneaking appear to do nothing. They certainly don't grant any skill bonuses. Note that these are different items than the Elixir of Hiding and the Elixir of Sneaking, which work perfectly. Also note that the Potion of Glibness, which has an identically structured .py file for its effect, DOES work just fine, so it's not a problem with the py file. The redundancy it items (elixirs and potions) grants two ways to fix this issue. The first is to replace all occurrences of these items is shops and chests with the corresponding elixirs. The second is to change the protos.tab entry for the items so that they trigger the same internal effect as the elixirs. Would one of these fixes seem to be more desirable than the other? I'd lean toward substituting in the elixirs, since having Potions of Hiding and Elixirs of Hiding is kind of stupid.