I never got to use the Qualleq in my arcana evolved campaign.

Here is my take:
Qualleq Magister
Level 15 Elite Controller (XP 2.400)
Medium aberrant magical beast (aquatic)
Initiative +10 Senses Perception +10; blindsight
Enveloping Liquid aura 1; The enveloping liquid creates difficult terrain. Any non-aquatic creature ending its turn in the aura is weakened until the
end of its next turn and the Qualleq can slide the target 3 squares to any other square in the aura. Creatures can choose to swim if they are fully inside the aura.
HP 296; Bloodied 148
AC 29; Fortitude 27; Reflex 28; Will 26
Saving Throws +2
Speed 6, climb 4 (Spider Climb)
Action Points 1

Tentacle Lash (at-will; standard)
The Quelleq shifts 1 square before or after the attack. ; +20 vs AC; 1d10 + 6 and slide the target 1 square.

Rays of Frost (at-will; standard) • Arcane, Cold
10; Targets one or two creatures within 2 squares of each other; +19 vs Fortitude; 1d10 + 6 cold damage and the target is slowed until the end of its next turn.

Blast of Cold (encounter; standard) • Arcane, Cold
Close Blast 5; +19 vs Reflex; 4d8 + 6 cold damage and the target is immobilized (save ends). Miss: Half damage and the target is slowed
(save ends).

Expanding Liquid (recharge 5 6; standard)
Special: This power is recharged when the Quelleq is bloodied and the Qualleq uses it immediately as a free action.
The Qualleqs aura increases by 2 squares until the end of his next turn.
Close Burst 2; Targets enemies only; +19 vs Reflex; 3d10 + 6 and the target slides 3 squares. Miss: The target is pushed 2 squares.
Deflecting Enveloping Liquid (recharge 5 6; immediate interrupt)
Trigger: The Qualleq is subject to an attack. Effect: The Qualleq gains a +4 bonus to his AC or Reflex defense until the start of his next
turn.
Alignment :Unaligned; Languages: Common, Deep Speech
Skills Arcana +18, Dungeoneering +15, History +18
Str 14 (+9) Dex 17 (+10) Wis 17 (+10)
Con 20 (+12) Int 23 (+13) Cha 17 (+10)