In order to complete Spyro The Dragon with 100% you have to unlock all trophies / achievements. In this guide we explain the following task to you:
Defeat all Metalback Spiders
The complete list of all trophies and achievement guides can be found here.
Find and kill all Metalback Spiders
You can do this task in the High Caves Level of Magic Crafters. Towards the end of the level you reach a large area with a Supercharge ramp. Inside the cave are Metalback Spiders (a total of 5), huge armored spiders that are insensitive to your normal charge and flame attacks. They can only be eliminated by using Supersprint or after being kissed by a fairy.
The best strategy for achieving this trophy is to use Supersprint for the first three spiders at the bottom of the cave and then use the superflame power-up to eliminate those in the higher area of the caverns. Remember to get rid of the green druids, which shrink and enlarge the cave entrances each time they use their magic.