There are from all chess systems some underground ones that are noted "dubious" from black ... but the one who analyses can find a transposition with reverse colours of the same system for white and finds himself in a good position.

The schliemann defense is an attempt to brake through the center from the beginning of the game in the Ruy Lopey system. It comes after 1. e4 e5 2. Nf3 Nc6 3. Bb5 f5!?

One could argue that this system is really complicated and it is, for sure one of the more tactical complicated ones.

As a bird player, it is somehow possible to reach one of the continuation of the system, but with reversed colours! ... so as to say, with a saved tempo and a greater evaluation?! not so sure...

An inverted Schliemann setup can be reach from the bird opening, in a curious form of the froms gambit where black denies its own gambit, after the following moves:

Yet, after analyse we realise that white can't take the knight without to give black at least a perpetual check (T. Taylor).