Complex sentence: It first attacks by transforming into various creatures from Link's past (Giant Bot, Agahnim, Moldorm, Ganon, and Lanmola), then transforms into a giant creature called DeathI and attempts to smash Link with its giant arms.
Split into simpler sentences: It first attacks by transforming into various creatures from Link's past (Giant Bot, Agahnim, Moldorm, Ganon, and Lanmola). After this fails, it transforms into a giant creature called DeathI and attempts to smash Link with its giant arms.