Hypno -> Mega Hypno
Typing: Psychic -> Psychic/Dark
Abilities: Insomnia / Forewarn / Inner Focus -> Bad Dreams [No need to have an identical ability with a new name guys]
85/73/70/73/115/67 -> 85/88/100/93/135/82 [+100 BST, +15 Atk/Spd, +30 Def, + 20 Sp.Def/Sp.Atk]
New Moves: + Dark Pulse; + Dark Void
Adding the Dark-type to Hypno, a pokemon infamous for it's abducting of children and generally adult fear concepts in addition to it's 'hypnosis' seems like a given to me. I'm somewhat surprised Hypno wasn't Dark Type to begin with. Bad Dreams is also a good ability for Hypno in my opinion, especially given that Hypno is a bulky pokemon.
As such, my stat spread favors bulking Hypno up a little. However, I also added some more offenses so Hypno can deal respectable damage with Dark Pulse and Psychic/Psyshock. Bearing in mind the Dark/Psychic STAB combination only exists on a physical attacker thus far, I think Mega Hypno could be interesting with this type combination. I was careful not to add a lot of speed, since a speedy sleeper is too dangerous: See; Darkrai.
Adding Dark Void is gonna be controversial, but Hypno is supposed to be about putting things to sleep. I think giving Hypno Spore makes no sense at all, and Hypnosis is only 60% accuracy. Dark Void is the only sleep move that is more accurate than Hypnosis which makes sense on Hypno. Darkrai is broken because it has 125 Speed and 135 Sp.Atk to back up Dark Void, Mega Hypno has far less speed and Sp.Atk. And dosen't sweep a team after a Nasty Plot created by a successful Void.
I bumped up Hypno's attack a little since Hypno can make use of physical sets as well. It has Zen Headbutt, Power Up Punch, Psycho Cut and all three E-Punches. A sleeper with PUP could be an interesting set.
Dewgong -> Mega Dewgong
Typing: Water / Ice - > Water/Ice
Abilities: Thick Fat / Hydration / Ice Body -----> Focused [Powers up 'Beam' moves by 50%]
BST: 90/70/80/70/95/70 -----> 90/70/110/95/120/90 [+ 30 Def, +25 Sp.Atk/Sp.Def, +20 Spd]
New moves: + Bubble Beam, + Psybeam + Charge Beam
I've always wanted Dewgong to be good, but the simple fact is medicore stats and the ice typing let it down.
This one took some thought, but eventually I decided Dewgong makes the most sense as a bulky special attacker. While I'd love to go physical because Narwhal concept, Dewgong has a pretty good special movepool, and physical ice... well... Mamoswine and Weavile and Avalugg are gonna outdo Mega Dewgong in that pretty much regardless of what we do. I mean, Dewgong gets Signal Beam.
Seeing this, I decided to break from my normal concepts, and actually give Mega Dewgong a new ability. 'Focused' is Mega Launcher for 'Beam' moves [Ice Beam, Signal Beam, Hyper Beam, Psybeam, Auroura Beam, Solar Beam, Charge Beam and Bubble Beam]
Of course, with many of these moves being stronger than the Pulse/Sphere moves of Mega Launcher, I have been careful not to raise M.Dewgong's Sp.Atk too much, especially with the addition of Charge Beam to it's moveset.
Mega Dewgong isn't that fast, but it hits hard with Focused Ice Beam.
Of note is that Mega Dewgong performs very differently to normal Dewgong. Mega Dewgong is an attacker, while normal Dewgong is usually a wall in the lower tiers, with tactics like Hydrarest.
Dodrio -> Mega Dodrio
Typing: Normal / Flying -> Flying / Ground
Abilities: Run Away / Early Bird / Tangled Feet -> Aerialate
60/110/70/60/60/100 -----> 60/130/85/60/85/140 [+20 Atk, +15 Def, +25 Sp.Def, +40 Spd]
New Moves: Drill Run, Bulldoze
The thing about Dodrio is that it isn't really 'normal'. It is a flightless bird. As such, Mega Dodrio embraces it, and takes away it's Normal typing for the Ground typing since it is a flightless bird [Giving it STAB Drill Run]. However, the loss of Normal STAB is not felt too hard, since Mega Dodrio gains Aerialate, giving it options for it's Flying STAB of choice. Thrash is brutally powerful but locks it in. Return is less powerful however.
This submission has a lot of power, but 60/85/85 is pretty glassy, especially with a water weakness and a quad ice weakness. Also a lack of priority means Mega Dodrio dosen't overshadow Mega Pinsir.
Muk -> Mega Muk
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Typing: Poison -----> Poison/Water
Abilities: Stench / Sticky Hold / Poison Touch ------> Poison Touch
105/105/75/65/100/50 -----> 105/105/110/105/125/50 [+25 Def, +50 Sp.Atk, +25 Sp.Def]
New Moves: + Doubleslap, + Duel Chop, + Muddy Water
My Mega Muk is more based around a gimmick than anything else. Muk's dex has long stated it is venomous to the degree it's footprints [Wait, it has feet?] are toxic. So I decided to have a little fun, giving Muk some multi-hit moves in tandem with Poison Touch.
So why bump up Muk's Sp.Atk and ignore it's physical attack? Because with the ability to inflict Poison at a very high rate with multi-hit moves or Poison Jab, Muk could be an interesting user of Venoshock. STAB Venoshock is disgustingly powerful, but no pokemon can really make much use of it, since in the time taken to envenom the enemy, you could have just Sludge Bombed or Poison Jabbed twice anyway. But Poison Touch allows Muk to go on the offensive from the start, switching to Venoshock when it poisons a target, through whatever way it achieves this.
The Water typing and Muddy Water were added because... well... look at Muk. It's liquid. Muk can easily be Water/Poison, and Muddy Water is a good thematic move, while also helping Special Mega Muk out. Mega Muk can run something like Poison Jab/Venoshock/Muddy Water/???
Or it can just use Sludge Bomb/Sludge Wave if it dosen't want to play the Venoshock game.
Of course, the defense boost means that good ol' CurseMuk is still an option as well.