My DD aged 2.8 is terrified of the hoover (we have Henry Hoover with the face on). I have to tell her every night that he can't get out of the cupboard. When I hoover she hides behind the sofa or goes to her Dad if he is in at the time. This started about 6 months ago when she saw a friend take my MILs hoover apart to get a blockage out. Before that she was fine with it.
She is also terrified of having a bath, especially water on her face.