Use an arena that is high and long and consider having the Stardust Dragon Staff. Kill them in the order: Twins, Destroyer, and Skeletron Prime.
Pinky is a rare slime that appears in the Forest. It is the smallest of the slimes, and has more health, defense and knockback than almost all of other pre-Hardmode slimes. However, it also has very low damage value. Note: The Slime Rain event greatly increases the spawn rates of all slimes native to the biome you are currently in. When one occurs, remain in the Forest biome to have a larger chances of encountering Pinky.
Crafting A Rainbow Rod requires the following ingredients.
Get a Blessed Apple, which is a mount item obtained during Hardmode (Post Wall of Flesh) from any hallowed enemies. The mount is the unicorn. You will also require the Rainbow Gun, which is obtained from the Hallowed Chest inside the Dungeon. The drop rate for the required key is very rare, from hallowed enemies only in Hardmode. The Hallowed Chest cannot be opened until Plantera is killed. Simply get on the Unicorn and shoot the Rainbow Gun to earn "Rainbows and Unicorns".
There are 21 town NPCs required. Some NPCs will appear in your town when you complete their individual requirements. Others appear tied up in various underground locations and must be rescued. The NPCs that must be rescued cannot be missed. If you are in the right biome and depth, the NPCs will respawn again near your location. Additionally, the following must be defeated for all NPCs to become available.
Get within five blocks of the very bottom of the map. To do this, reach the Underworld then find a deep-reaching Underworld tower. Dig through the floor into the ash until you reach the bottom while avoiding pools of lava. To make this easy, try to have the following.
This yoyo drops from the Moon Lord about 11% of the time. You may also be able to get one from another player.
There are a total of fourteen Bosses that must be killed. Note: Event Bosses do not count.
When a Slime Rain event begins, remain aboveground and fight slimes. At the end of the event, King Slime will attack. Slime Rain spawns normal slimes for that biome.
Survive the slime rain and defeat the King Slime that will spawns after you kill 150 slimes during that time. Note: If the King Slime was previously defeated, only 75 slime kills are required to make him appear again.