The first cycle is red (image to the right). When right-clicked, it will turn a 3x3 area into Netherrack.
The second cycle changes from yellow to orange. When right-clicked, it will act like a lava bucket and places lava that cannot hurt the placer or burn up items, making it useful for mob traps.
The third cycle is brownish grey. When right-clicked, it will turn a 3x3 area into Soul Sand.
The fourth cycle is black with speckles of grey. When left-clicked, it will shoot a Wither Skull that has the same effects as one shot by a wither itself, but with both types of skulls comined into a dark blue. When right-clicked, it will spawn a Wither that will obey the Player and have the same behavior pattern as a dog. But much more dangerous.
The fifth cycle is white. When left-clicked, it shoots a Ghast Fireball. When right-clicked, it will spawn a Ghast that obeys the player.
The sixth cycle is very dark red. When left-clicked, it shoots three Blaze Fireballs. When right-clicked, it spawns a Blaze that obeys the player.
The seventh cycle is pink, grey, and green. When right-clicked, it spawns three Zombie Pigmen that obey the player and attack anything else that attacks them in a group.
The eighth and last cycle is orange and black. When right-clicked, it spawns a full-sized Magma Cube that obeys the player.
Note that if the player presses F, it will cycle between Corrupted versions of the mob-spawning cycles, meaning that the Player can spawn a group of obediant Wither Dragons to destroy almost anything. The only Nether mob that the Pearl of Eternal Nether cannot spawn is a Wither Skeleton/Jockey. The spawner of the nether mobs cannot be hurt by them, even if he/she hits them. When held in the hotbar, it will increase damage done with bows and swords by 5 <3.