Simplest strategy is to use the Zica Flamethrower to destroy the webs, stay out of range of the legs until the eye opens - and then destroy a leg when it does open. Once you've done this seven times (and its movement has become an erratic hopping instead of a calculated attack) it will be much easier to damage the boss itself when (as usual) the eye opens. Takes a long time, but you're basically perfectly safe. Don't accidentally destroy that last leg, though!