Culture Fluid (培養液 Baiyōeki) is an acid-like ooze that appears in Dragon Ball Z: Bio-Broly.
Its primary usage is as an incubation fluid for various clones and Bio-Warriors in Mei Queen Castle. Although the Culture Fluid itself is harmless when contained, when it is exposed to air, it quickly becomes corrosive, resulting in its acid-like properties. This ooze melts every living thing that gets in its way, and absorbs it into itself, increasing in amount.
The Culture Fluid was released by Bio-Broly, the clone of Broly the deceased Legendary Super Saiyan, when he transformed into his Legendary Super Saiyan form, shattering his tank before the fluid could properly be drained. Although an attempt at containing the fluid before it could become corrosive was used by putting up barriers, Bio-Broly proved to be too strong for the barriers to contain, shattering them. Its first victim was Hei, who foolishly jumped into it, despite Lord Jaguar's warnings. It also killed all of the Bio-Warriors as well as most of the scientific personnel and Maloja, but only deformed the monstrous Bio-Broly. The battle against Bio-Broly caused severe collateral damage, which knocked open many more tanks containing Culture Fluid, rapidly flooding the island while increasing the casualties. After a fight against the mutated Saiyan clone, Trunks thought back on all the people that were killed by the Culture Fluid, and decides to try and lure Bio-Broly underneath a tank containing the Culture Fluid and then destroy it with a Ki Ball. However, the plan had a slightly delayed effect, and it only succeeded when Trunks was at Bio-Broly's mercy, apparently killing Bio-Broly. In reality, Bio-Broly had merged with the Culture Fluid and it had become far too powerful to contain.
It seemed as if all hope was lost until Mr. Satan inadvertently exposed the weakness of the Culture Fluid by diving into the ocean: it solidifies into a rock-like substance upon coming into contact with water. Goten, Trunks, and Krillin, with this newfound knowledge, exploited the weakness by firing a triple Kamehameha at the ocean to cause a tidal wave to cover Jaguar's island and solidify any remaining trace of the Culture Fluid. However, Bio-Broly resurfaces as a giant because of having merged with the Culture Fluid, but due to his being drenched with water, he solidifies, allowing Trunks and Goten to destroy him, ending the clone's existence.