Priest · Shadow Magic · tier 3 · from level 20 · needs Mind Flay
Improved Mind Flay
+76.1 Mind Flay
2/2 · level 60 · per cast
Improved Mind Flay
Rank 2/2
Your Mind Flay now deals 20% more damage, gains 10 yards increased range, but slows the target's movement speed by 20%.
Averages, counting crits and misses, for a level 60 Priest with a typical weapon and no other gear or buffs, against a target your level. Worked out from the game's own data, the same way as the Foresight addon.