
If you Increase the Grox's disposition with you (by doing lots of missions/socialisation for them), you should be able to get to the core without being ambushed by Grox ships, this should allow you to find a good place to start the attack, but remember, as soon as you hit the first city, you will declare war on them and they will attack, so choose wisely. It is easy to tell when a spaceship will use a mega repair pack, they fly to a safe spot. Many of the Grox's colonies contain only one unfortified city, but the cities get defended more heavily as the player nears the core, so a viable strategy would be to start with the core systems, as this will be more useful in the long run than whittling them down from the outside, as that will exhaust more resources and give the Grox more time to attack you.
Terraforming a planet to T1 will remove the Grox from the planet, so prepare accordingly. The Grox have few weaknesses and have formidable ships. The Grox control exactly 2,400 systems and about 5,000 planets and therefore will take a lot of time. They have a light source coming from under the creature, instead of above them, in the thumbnail.Eradicating the Grox is difficult to do, even on easy difficulty or with cheats. The created creature will be placed in your Sporepedia, the created creatures are easy to differentiate from creatures created with the normal editor. Like in the Creature Stage editor, the player can only use parts that they have already "collected" by scanning or abducting creatures that have them. It opens up a unique version of the Creature editor rather than the background being a lush forest like it usually is, this time it takes place in a high-tech genetic engineering laboratory. This tool allows the player to create a creature and places 5 of them into the cargo hold for populating planets.
"Makes a creature and five specimens of it in your cargo hold."