What is the most powerful move with a secondary effect?

Question

title.

Answer 1

Okay I missed some actually. The real ones are Sky Attack, which can cause flinching, Freeze Shock, which can paralyse, and Ice Burn which can burn opponents, all at 140 BP.

There are of course moves that force user's stats to drop like Psycho Boost or Leaf Storm but these aren't Secondary Effects as far as the game classifies them via abilities like Sheer Force

If you want to count any literal secondary effect, then it's Explosion, which causes the user to faint at 250 Base Power.

Comments

Thanks :P
filler

Answer 2

Sky attack has base 140 damage and 30% chance to flinch and high crit ratio. Overheat has base 130 damage and lowers your SpA 2 stages.
Source: PS!