Since lowball is usually played with the bug, and other forms of draw poker are often played with the bug (west of the Mississippi, at least) I will digress now to discuss special considerations applying to any game in which the bug is used.
You know, of course, that the bug is the joker; but it is not the joker as an unrestricted wild card. The joker defined as the bug can be used only as an extra ace or to fill a straight or a flush.
In lowball, in which the ace is the lowest card instead of the highest, and in which straights and flushes do not count, the bug occupies a unique position. If there is no ace in the hand, the bug is simply the ace, the lowest card. If there is a natural ace in the hand, the bug never pairs that ace. It simply ranks as the missing card next higher than the ace. Therefore the hand 5-4-3-2-A (natural cards) cannot be beaten by the hand 5-3-2-A-