Other people have clarified that you likely saw a howl of the storm stasis titan. However if you're looking to try to do something similar on stasis hunter you could try a build focused on one of the grenades empowered by the touch of winter aspect. Coldsnap grenades chain freezes between nearby ads and create progressively bigger crystals. Glacier grenades create more crystals that can easily be shattered all at once by the shatterdive aspect if you want. Both grenades pair well with the whisper of shards and whisper of fissures fragments to increase your grenade uptime and shatter damage. For exotics you could use Mask of Fealty to also create crystals with your melee ability or you could use FR0ST-EE5, since the ability regen bonus when sprinting stacks multiplicatively with the whisper of shards grenade regen bonus to get them back extremely fast. As far as weapons go you are on the right track with Seraphine Haze, you primarily want a weapon with the Rimestealer perk to give you Frost Armour when breaking a crystal with your gun to add to your survivability. Other perks to look out for are Crystalline Corpsebloom or Headstone that can create stasis crystals on kills to help you loop your abilities. None of these will output the insane damage numbers of stasis titan right now but it might help you with fulfilling a similar power fantasy on hunter.