DNA Donors: Yanmega and Darkrai
Offspring Name: Darmega
New type: Dark/Bug
New base stats: 90 (+12)/83/88/140 (+15)/76 (+3)/120 (+10) (BST 597)
New ability and desc: Dream Crusher (Tinted Lens + Bad Dreams): The user deals 2x damage to sleeping targets.
Notable Moves: Disable, Dark Void, Nasty Plot, Dark Pulse, Taunt, Ice Beam, Thunderbolt, Psychic, Sludge Bomb, Focus Blast, Will-O-Wisp, Icy Wind, Trick, Bug Buzz, Air Slash, Ancient Power, U-Turn, Roost, Giga Drain, Tailwind
Role identification: Just something that absolutely abuses sleep. Put the mon that walls you the hardest to sleep, and suddenly it's not a problem anymore. 140 SpA combined with 120 Speed is terrifying, and the Dark/Bug STAB combo is nothing to sneeze at either.
EDIT: One more!
Parents: Exploud and Lucario
Shared Egg Group: Field
Offspring Name: Lucalroud
New type: Normal/Fighting
New base stats: 97/110/76/113/81/89 (BST 566)
New ability and desc: March Band (Soundproof + Steadfast): The user's speed is boosted by 1 stage every time a sound-based move is used on field.
Notable Moves: Boomburst, Roar, Crunch, Taunt, Ice Beam, Earthquake, Return, Shadow Ball, Flamethrower, Fire Blast, Overheat, Focus Blast, Rock Slide, Power-Up Punch, Surf, Circle Throw, Hammer Arm, Fire Punch, Ice Punch, Icy Wind, Low Kick, Thunder Punch, Zen Headbutt, Extreme Speed, Close Combat, Aura Sphere, Swords Dance, Calm Mind, Bulk Up, Psychic, Shadow Claw, Stone Edge, Poison Jab, Flash Cannon, Dark Pulse, Agility, Blaze Kick, Bullet Punch, High Jump Kick, Vacuum Wave, Drain Punch, Focus Punch, Iron Tail, Nasty Plot
Role identification: Yeah, it's another STAB ESpeed user. That's not the main point here, though, since the best thing of this fusion is that it can now abuse spamming sound-based moves, namely, STAB Boomburst. Slap a Specs on it, click Boomburst, and watch as it approaches sonic speed while hitting everything like a truck. Or, y'know, a pseudo-double dance set with Nasty Plot/Calm Mind and March Band-boosting Boomburst works too. Too bad that and Hyper Voice are the only usable sound-based moves Exploud learns...