Eldegoss @ Heat Rock
Nature:
Offensive:
Modest (+Sp. Attack, -Attack), Quiet (+Sp. Attack, -Speed)
Defensive:
Calm (+Sp. Defense, -Attack), Sassy (+Sp. Defense, -Speed), Bold (+Defense, -Attack), Relaxed (+Defense, - Speed)
Trait: Cotton Down (Synthesis) or Regenerator (Growth)
EVs:
Offensive:
(1) 252 Sp. Attack, 252 HP, 6 Sp. Defense
(2) 252 Sp. Attack, 252 HP, 6 Defense
Defensive:
(1) 252 Sp. Defense, 252 Defense, 6 HP
(2) 252 Sp. Defense, 252 HP, 6. Defense
(3) 252 Sp. Defense, 252 Defense, 6 Sp. Attack
Moves:
Sunny Day: Causes Harsh sunlight for 5 turns, 8 turns if Eldegoss is holding the Heat Rock. This move will effect Solar Beam, Growth and Synthesis. It effects lots of other moves, but the 3 listed above are the ones in this moveset. Sunny Day can only be taught to Eldegoss by TM.
Solar Beam or Cotton Guard:
Solar Beam takes one turn to charge, and the next turn it attacks. Solar Beam does not need to charge if the move sunny day is in effect. Solar Beam is STAB, and uses Sp. Attack. Solar Beam can only be taught to Eldegoss by TM. Combine this move with Sunny Day, and you can do some serious damage with Eldegoss. Cotton Guard increases Eldegoss's Defense Stat by 3 stages. With this amount of defense, Eldegoss shouldn't take to much damage.
Growth or Synthesis: Both of these moves are effected by sunny day. Growth increases the users Attack and Sp. Attack by 1 stage. When Sunny Day is in effect, it raises the Attack and Sp. Attack stats by 2 stages. This can be useful after using Leaf Storm, which lowers the users Sp. Attack by 2 stages. Growth will increase the power of Both Solar Beam and Leaf Storm. The only way Eldegoss learns Growth is by Breeding. Synthesis recovers 1/2 of the users max HP, 2/3 of the users HP when Sunny Day is in effect.
Leaf Storm: This move gains STAB, and does the same amount of damage that Solar Beam does. The downside to this move is that it lowers the users Sp. Attack by 2 stages. This can be recovered by using Growth when Sunny Day is in effect. Be sure to use Growth (when Sunny Day is in effect) before attacking that way, you get the boost of Sp. Attack, so Leaf Storm does more damage, THEN lowers the Sp. Attack.
Other move suggestions:
Magical Leaf, Aromatherapy, Energy Ball
Hope this helps!
Note:
Moves leaned by Level Up:
Synthesis (level 28)
Leaf Storm (level 46)
Cotton Guard (level 52)
Aromatherapy (level 40)
Moves learned by TM/TR:
Solar Beam (TM11 Sw/Sh)
Sunny Day (TM34 Sw/Sh)
Magical Leaf (TM10 Sw/Sh)
Energy Ball (TR65 Sw/Sh)
Moves learned by Breeding:
Growth (Possible Parents: Bulbasaur line, Oddish line, Seedot line, Roselia and Roserade, Cherubi line, Cottonee line, Maractus, Phantump line, Flapple and Appletun)