Assuming a watery form lets your target slither through the enemy ranks to get into position to make a attack or to escape.

Encounter   ✦     Arcane
Move Action      Close burst 5

Target: You or one ally in the burst

Effect: The target can use a free action to shift up to a number of squares equal to your Intelligence modifier. The target can shift through enemy spaces.

Published in Heroes of the Elemental Chaos, page(s) 114.