What/where/who the blazes…?
Definition 1 of 1
Pro Tip 1/3Emotional Intensity
Shows strong emotions like shock or irritation. Be cautious using it to prevent sounding rude. 
What the blazes are you doing with my car?
Pro Tip 2/3Colloquial Tone
Primarily used in casual conversations, not in formal situations. 
Who the blazes left the door open?
Pro Tip 3/3British Origin
This phrase is more common in British English, so it might be less recognized by other English speakers. 
Where the blazes did you find that hat?