I'd like to bring this bad boy up to discussion
Mega Houndoom is an absolute BEAST when it's given the chance. It has one of the most powerful attacks in Fire Blast under sun that ever was and it has Nasty Plot to pile on top of that. I've been using it lately (not only bc doom is my favorite poke of all time) and it crushes the opponent. The only things it really fears are priority from strong fighting types but it is just so powerful and fast someone use it so I can share my excitement for this thing.
I use it with Whimsicott to set up sun. Here is my Houndoom set (pretty basic)
Houndoom (M) @ Houndoominite
Ability: Flash Fire -> Solar Power
252 SpA / 4 SpD / 252 Spe
Timid Nature
-Nasty Plot
-Fire Blast
-Dark Pulse
-Solarbeam
I know it has other cool options like setting up its own sun or Destiny Bond, but I went for set up and sweep with no other inhibitions and it has gotten me through late game sweeps incredibly (even without priority). Snorlax (and some bulky waters if you don't run Solarbeam) can screw you over, but Doom is so great rn tbh
Just thought I'd throw something in there.