These weapons and augs just for the special task of killing "A glob of goo" because it has
Highly Freezable modifier on it for
x100 damage from ice things. Most classes struggle to contribute in killing them because regular damage is near worthless; those classes contribute better just suppressing adds. Not beastlords; beastlords if they go for it have tons of ice-specific damage with which to move Phase 2 toward a win.
That's just the "A glob of goo". Everything else takes regular damage so bst should use regular weapons and cast regular spells for killing animated weapons and undeads and noodles and golems and sarnak.
The regular kit for beastlords should already include
Nra`Vruu's Sympathetic Stone slotted to their range item.
Beastlords should have
Tonic of Resonant Frost for this task, to add more ice damage to the ice spells they chain cast on A Glob of Goo. Chain casting Chill dot is highest dps.
Gelid Rending AA adds ice procs to beastlord attacks with h2h and 1hb weapons. Not piercers, not 2h. So, weapons:
1hb
Teal Sky from named
Triumphal Still Sky in Stratos, with augment
Frosted Topaz from
A Ry`Gorr Inspector in Crystal Caverns (level 100 RoF version)
1hb
The Calm from
Head Boiler Akett in Gorowyn with augment
Deepwater Freeze from
Eldaa Kemph in Cooling Chambers
the
Siren's Demise augment from TDS mission currency is stronger than the listed augs - it's for sure an available upgrade if the beastlord has Immortal Gem of Stone to go with Venomous Tear in their "real" weapons, but may already be occupied.
Warders should have magician-made
Summoned: Gorstruck Iceblades