Priest · Shadow Magic · tier 5 · from level 30
Devouring Contagion
+84.0 Devouring Plague
2/2 · level 60 · per 100 mana
Devouring Contagion
Rank 2/2
Reduces the mana cost of your Devouring Plague by 50%. Targets that die while Devouring Plague is active spreads it, jumping to a nearby enemy within 10 yds for the remaining duration.
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.