Flowing Evasion is a Encounter power available to Wizards at 10th level[HotEC]

Flowing Evasion
Wizard Utility 10

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

Encounter ✦ arcane

Close burst 5

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.