On crystal.isles these are NOT tameable at the moment, so you will either have to spawn in a pair of magmasaurs and breed them for eggs or spawn rockdrake eggs, I would go for magmasaurs as they are breedable and rockdrakes aren't. Hope this was useful.
If you are looking to get a basilisk on crystal isles don’t even try without forcetame or spawn rock drakes due to the drakes not spawning. Thanks for adding acid spitting snakes on the map TAHT CANT BE TAMED
Taming a Basilisk is simple. First you throw a light let on the ground, and place a metal foundation over it and switch the foundation to block form. Then drop all the eggs on top of the metal foundation and lure the basilisk to the foundation. It will focus on the bulldog, but cannot damage it.
For the people who tried the trick the people in comments are spamming didnt work, you actually have to throw the pet on the ground and place a metal foundation (others dont work) OVER IT (yes you can place it over a shoulder pet) then switch to block and continue taming the snek