Web is a daily power available to Wizard at 5th level[Dr401]
Web
Wizard Attack 5
You create a giant web of thick magical strands that hangs in midair, trapping those within it.
Daily ✦ arcane, implement, zone
Area burst 2 within 20 squares
Target: Each Creature in the burst
Attack: Intelligence vs. Reflex
Hit: The target is immobilized (save ends)
Effect: The burst creates a zone of difficult terrain that lasts until the end of the encounter. Any creature that ends its movement in the zone is immobilized (save ends)