Just an idea that came to me in a dream a while ago. A trio of girls end up in a magical land and, using elemental powers, must fight to free this land from an evil force. Yeah, it's similar to Magic Knights Rayearth (hell, it could be a doujin idea). The chief difference is that the enemies they face are all quite savvy about handling magical girls and the girls in this series are hardly the first to try to free the land from evil.

One such foe (a sorceress) has the ability to strike magical girls when they are at their most vulnerable: their transformation sequences. Using a special spell, she can corrupt their transformations mid-way and cause them to transform into monsters instead of their normal form, as well as rendering them unable to change back. She does this in a public space and convinces those nearby that the heroines are actually monsters trying to trick them and that she has "revealed their true nature".

The monster forms humiliate the magical girls and cause them to lose favor with the people. Faced with this, most magical girls are killed by the townsfolk or lose their will to continue. However, corrupted though it may be, it is STILL a magical transformation and they do possess some of their elemental abilities, though few last long enough to figure them out.

This is the "Hikaru" of the group, who has the ability to breathe fire (the "Umi" can swim fast and the "Fuu" can fly). The three manage to escape the village and gain the trust of a girl who Umi saves from drowning, at the same time accidentally discovering the abilities their new forms have. They manage to return, confront the Sorceress, and destroy her staff, thus reversing the corrupted form, the first group to do so. Said sorceress is soon made an example of by her boss.

They soon discover that they are still able assume these forms. While slow, ugly, and lacking in offensive magic, these forms have the benefit of granting better physical strength, a different set of special abilities, and can be maintained indefinitely (their normal magical girl forms only last a few minutes). The girls eventually get over their aversion to the unpleasant appearance of this form thanks to its benefit. ("Fuu" gets over it right away, since it gives her the ability to fly).

Ah well, been trying to put the design on paper, and I was going for "Just ugly enough". Did I succeed, or can someone do better?