[3.5] Ways to learn spells from a different class list

[Morcleon]

Then you could also pick "42" as the level, for any spell, if there's no rule.

Except for the fact that control water is either a 4th or 6th level spell. Also, a bard is incapable of casting 42nd level spells.

It's a matter of common sense and discussing it with your DM.