Combos Utilizing Sunweb

After declaring Sunweb as a blocker, pay W to give it first strike. It will kill a creature up to a toughness of five before it takes damage.

4 for 5/6 flying which costs 1 to attack

A 5/6 creature for 4 mana doesn't sound too bad to me.

Put Altar of Dementia in play. Declare Sunweb a blocker & cast Glyph of Destruction. Sac the wall to the altar & make opponent put 15 cards from his library into his graveyard.

block with a wall, glyph of destruction or righteousness the wall twice, then, after damage is assigned, fling it to the opponent for at least 20 damage. i usually like to use a sunweb as the wall.