Anyone ever play Omega Boost? (god, that game went ignored... WAY overdue for a PS2 remake). The final boss was nearly impossible, as is the cliché for final bosses. This HUGE metal behemoth launching its arms at you, with energy teathers inbetween them. After that, you had about 8 seconds to destroy his gelatinous core or it'd explode, taking you out with him.
And damn, that game had great music, too...