Drustcraft has Skyblock type worlds that sit above overworld worlds.
To get to a Skyblock world, you need to drink a "potion of ..." potion to teleport you upwards. Note that where you drink the potion is important as you will be teleported to the corresponding location in the Skyblock world.
Corresponding does not mean exact! Just like the nether, which has a 1 to 8 ratio of position, Each Skyblock world has a different ratio!
Falling from a Skyblock does not mean an instant death! As Skyblock worlds sit above overworlds, you will fall from the Skyblock world and land into the corresponding overworld. If you are lucky, you will land in a body of water and survive!