Hydra with Grand Arrival also applies the Grand Arrival effect of the Ritch Flamespitter (ie both the poison cloud and the burst that lowers fire resist). The code reads:
on_arrival = function(self, t, m)
local tg = {type="ball", range=self:getTalentRange(t), radius=self:getTalentRadius(t), talent=t, x=m.x, y=m.y}
self:project(tg, m.x, m.y, DamageType.TEMP_EFFECT, {foes=true, eff=self.EFF_LOWER_FIRE_RESIST, dur=4+self:getTalentLevelRaw(t), p={power=self:combatTalentMindDamage(t, 15, 70)}}, {type="flame"})
game.level.map:addEffect(self,
m.x, m.y, 6,
DamageType.POISON, self:combatTalentMindDamage(t, 10, 40),
self:getTalentRadius(t),
5, nil,
{type="vapour"},
nil, false
)