Alrighty, most people think the side I favour on this topic but Fred won't listen to me unless I post, so.
First I'll mention the moves:
Destiny Bond
Flamethrower/Fire Blast
Endure
Reversal
Pursuit
Crunch
Super Fang
Taunt
Hidden Power Ground or w/e
Sunnyday
Solarbeam
Current UU Usage
As you can see in the link above, there isn't much currently outspeeding houndoom besides Manectric, Tentacruel, Gligar (Jolly Gligar, not +Speed Doom), which is meaning when you finally are able to kill it, it can use Destiny Bond, gg free kill.
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Next, with Psychics/Ghost types being the best check to Hitmonlees Superpower. Once that happens, bring in your Houndoom and Pursuit on switch, or Crunch, or Shadow Ball:
252+ Atk Houndoom Pursuit vs. 252 HP / 252+ Def Xatu: 104-126 (60.4 - 73.2%) -- guaranteed 2HKO after Leftovers recovery
252+ Atk Houndoom Crunch vs. 252 HP / 252+ Def Hypno: 104-126 (54.1 - 65.6%) -- guaranteed 2HKO after Leftovers recovery
252+ Atk Houndoom Pursuit vs. 252 HP / 252+ Def Misdreavus: 116-138 (69.4 - 82.6%) -- guaranteed 2HKO
252+ Atk Houndoom Pursuit vs. 252 HP / 252+ Def Claydol: 84-98 (50.2 - 58.6%) -- 64.8% chance to 2HKO after Leftovers recovery
Yes, Claydol can take a Crunch/Shadow Ball
0 SpA Houndoom Shadow Ball vs. 252 HP / 0 SpD Claydol: 56-68 (33.5 - 40.7%) -- 38% chance to 3HKO after Leftovers recovery
0 Atk Claydol Earthquake vs. 0 HP / 0- Def Houndoom: 162-192 (108 - 128%) -- guaranteed OHKO
But keep in mind, this now leaves Claydol wide open for Lee to Superpower away.
252+ Atk Houndoom Pursuit vs. 252 HP / 252+ Def Exeggutor: 96-114 (47.5 - 56.4%) -- 75.4% chance to 2HKO
252+ Atk Houndoom Pursuit vs. 252 HP / 252+ Def Girafarig: 110-132 (62.1 - 74.5%) -- guaranteed 2HKO
252+ Atk Houndoom Pursuit vs. 252 HP / 252+ Def Grumpig: 110-132 (58.8 - 70.5%) -- guaranteed 2HKO
If they stay in Crunch will do the same damage.
You could say Porygon2 stops this and the SunnyBeam, yet it can't beat the Endursal, as Yagami posted above.
Walrein?
+1 252+ Atk Houndoom Reversal (200 BP) vs. 252 HP / 252+ Def Walrein: 226-268 (104.1 - 123.5%) -- guaranteed OHKO
0 SpA Houndoom SolarBeam vs. 252 HP / 0 SpD Walrein: 108-128 (49.7 - 58.9%) -- 74.2% chance to 2HKO after Leftovers recovery
I know I'm missing more SunnyBeam/Reversal set calcs, but I have to do some things before work. I'll hopefully get to it tomorrow. (sorry)
Pretty much mispredict the set, and this can put a major whole in your team.