In tonight's auditions we see Krystyna Lennon and her hypno-dog, a German Spitz called Princess, perform their hypnosis double-act on audience members as well as hosts Ant & Dec.
Krystyna claims: "Princess is the world's only hypno dog. She looks into people's eyes and they just fall to sleep."
She promises to show the judges "something they've never seen before."
After picking a selection of volunteers from the audience, Krystyna asks them to kneel before Princess one by one and they each end up falling to sleep on stage in a pile.
And once she's woken them up out of Princess' trance, Krystyna reveals how they've forgotten the number seven.
Hosts Ant and Dec are left puzzled as they attempt to count up to ten on their fingers.
Simon Cowell declares: "I don't know what the hell's going on there," but says he wants to see "more crazy" things from the supposed hypnotising pet pooch.
Getting on stage to try the act himself, Simon seems to be immune to Hypno-dog's charms as he returns to the judges' desk fully awake and unimpressed.
"It's just a dog with a big tongue staring at me," he says.
But as the auditions continue it seems that there is something is very different about Simon...
You can watch the full audition when Britain's Got Talent airs tonight at 8PM on ITV.
Other hopefuls on tonight's auditions include a acpaella group, a gospel choir, a man who plays a moving piano and a can-can-ing drag act.
Browse pictures of all of tonight's Britain's Got Talent 2015 contestants here...