From the dark, murky depths of my memory, I have brought up the worst spellcard ever. It will destroy FallenV, Kefit, Donut, SirAlex, you name it. They will all fall before this.
It's technically a survival spellcard. There is no visible boss, and no lifebar. You have no option but to time it out. Once every five hours, a random bullet will fall* from the top of the screen. There is no way to predict just when in these five hours the bullet will fall.
Upon beating the first wave (one bullet), the cycle of five hours will begin again. Rinse and repeat until five bullets have fallen. This will take you, on average, 24 hours around the clock. When you beat it the first time, you will get a spellcard bonus of one point; when you beat it the second time, the words GO OUTSIDE will flash in big yellow letters across the screen, and so it will with each time you beat it next.
*And by "fall" I mean "home in on you like Fantasy Heaven, except twice as fast and half as fair".