To obtain this particular cursed seal, the chosen person is bitten by a snake to receive the instructions on how to form the potion that grants the user a seal, rather to have one directly given through a bite from Orochimaru like the rest of his cursed seals.
When the ingredients are formed into the potion and then ingested, the user will go into the first stage of the cursed seal and obtain enhanced abilities along with muscle growth and, in Mizuki's case with his tiger-like stripes, traits of an animal.
When the second level is reached, the user will attain the form of an animal along with the increasing strength and abilities, but decreased speed.
However, if the potion for the seal is consumed earlier than it is intended, then the results will backfire and the person's body will begin to destroy itself. In Mizuki's case, when the potion effects dissipated, he shrivelled up into an angry and powerless old man, and would have died if not for Tsunade's medical skills. Regardless, Mizuki lost all of his powers and could never be a ninja ever again.
