ITT: Only the shittiest of competitive balance changes

Megas can now hold held items
Rain cuts Flying-Type's Speed by half
Stealth Rocks now OHKO's Pokemon weak to Rock
Rapid Spin no longer removes entry hazards
Blizzard takes away one quarter of the user's HP, when used in Hail
Rock, Water, Poison and Ground-Types now resist Bug-Type moves
Intimidate now lowers the opposing Pokemon's Special Attack, in addition to lowering their Attack
Unnerve has a chance to cause paralysis to the opposing Pokemon, upon activation of the ability
All moves with a chance to freeze, now have a 100% chance of freezing the enemy Pokemon