several ways to use her:
Froslass @ Life Orb
Timid Nature
252 SPD/252 SP ATK/4 HP
-Ice Beam
-Thunderbolt
-Shadow Ball
-Destiny Bond
simple concept. attacks what it can and then goes on for death.
Froslass @ Choice Specs
Timid Nature
252 SPD/252 SP ATK/4 HP
-Ice Beam/Blizzard
-Thunderbolt
-Shadow Ball
-HP Fighting/Light Screen/Destiny Bond
choice specs + unsuspected support move is always a nice touch.
Froslass @ Lum Berry/Leftovers
Timid Nature
164 SPD/196 HP/148 SP DEF
-Block
-Toxic
-Hail/Protect
-Taunt
toxic trapping froslass. destroys blissey with block + taunt and toxic reduces its life to nothing in a matter of 6-8 turns, which means you'll have to use taunt more than once. it also does well against special bulky waters like Suicune and Slowbro who depend on Calm Mind and Ice Beam.
Froslass @ Leftovers
Timid Nature
252 SPD/252 HP/4 SP ATK
-Blizzard
-Thunderbolt/Confuse Ray
-Hail
-Light Screen/Protect
stalls and gives light screen support.
Froslass @ Choice Band
Jolly Nature
252 SPD/252 ATK/4 HP
-Ice Shard
-Wake-up Slap
-Crunch/Light Screen
-Destiny Bond
mainly for ice shard to hurt unexpectingly hard and wake-up slap to hurt blissey some. crunch is for other ghosts and starmie using ice beam. destiny bond is self explanatory.
Froslass @ Life Orb
Timid Nature
252 SPD/252 SP ATK/4
-Block
-Taunt
-Destiny Bond
-Thunderbolt
self-explanatory. trap them, taunt them if they think they know better, and take them out with destiny bond. if whatever comes into block has every intent of killing you, then you should just start off with destiny bond. thunderbolt is for skarm+gyara+whoever else is weak to tbolt and is slower.
finally,
Froslass @ Choice Scarf
Rash/Mild Nature
212 SP ATK/144 ATK/152 SPD
-Ice Beam
-Thunderbolt
-Wake-Up Slap
-Destiny Bond
even with base 110 speed, it is still considered slow nowadays with everything running rampant with choice scarf. so here is the solution -- give it choice scarf. after gyara DD's, it's still way faster than it. it's faster than weavile and most tyranitars after 2 DDs, which it can OHKO them now. it's faster than Choice Scarf Porygon-Z who thinks its clever with double STAB Tri-Attack and has that weak to fighting. it's faster than most choice scarfers with X4 ice weaks like Garchomp, Flygon and Salamence. it's faster than starmie who is otherwise faster than froslass.
this froslass is overall a nice finisher and a nice surprise.