basically the idea with the sonic bloom is that as the underground dark world expanded it'd reach waterfall, and the echo flowers there would become these creatures called sonic blooms. sonic blooms mimic any sound they've heard, like talking, as a means of fooling and attracting prey, and I imagine that once flowey has adjusted to the dark world he controls these as minions. as shown by the strange deterioration of the text they're speaking, their mimicry is flawed and can get less accurate with repetition, sort of like a toy's voice box that's running low on battery. I imagine they'd attack using sound blasts, petals/vines/other plant parts, and maybe even something similar to flowey's friendliness pellets
