
Originally Posted by
Kraleck
A few things could happen, though:
-Your Water Type is too weak to survive another hit (or worse, KO'd)
-You could be Burned by WoW or a damaging Fire-Type Move on a switch
-Pokemon with Intimidate could drop your Attack a few times and possibly carry Fire Type Moves (Arbok, Arcanine, Tauros, Mawile, Salamence, Staraptor*, Luxray, Stoutland)
-You face a high Defense-low Sp.Def Fire Type (Torkoal or Magcargo)
-You face a high Defense-low Sp.Def Pokemon that resists Bug Type Moves in-general (Aggron, Skarmory, Steelix, Golem, Gigalith)
-Cofagrigus enters hoping to screw you out of further Bug-Type Move boosts or Critical Hit blocking
-Counter and Metal Burst users could 1KO you from Megahorn use
-You could miss entirely (Megahorn's accuracy is 85% and you could be further hindered by Muddy Water, Mud Bomb, or a lucky enemy's Acupressure)
Protecting your Attack from hindrance is as important as KOing any Pokemon that can hinder it. Without your key offensive stat, you will have a ton of issues. Rain + HP (Water) is a safety net.
* Doesn't carry Fire Type Moves outside of a random Heat Wave, but it's very unlikely.