After completing Rocking Out, players may buy 'rum' at The Rusty Anchor Inn in Free-to-play worlds, but they will be unable to drink it as it is a members-only item.
Even with all the disgusting ingredients used to make the 'rum', it still heals some life points when you are hurt. However, the decreases in most combat skills makes it unwise to use it as emergency healing (not to mention that it has a small delay after consumption before the stat changes take place).
Despite being a drink of sorts, it makes the "crunching" sound when consumed, as if it were solid food. This may or may not be the corpse of the fever spider in the drink.