In the game "Plants vs. Zombies," there is no official character or item referred to as "Disco Tron 3000." It's possible that you may be referring to a custom modification (mod) created by the game's community, or it could be a misinterpretation or misunderstanding of the game's content.
"Plants vs. Zombies" does have a variety of unique plants and zombies, each with distinct abilities and characteristics. The game also includes a time travel-themed level called "Big Wave Beach" where you might encounter various beach-themed zombies and plants that can be reminiscent of the 80s or disco era. However, the name "Disco Tron 3000" does not correspond to any specific part of the game's official content.
If you've encountered this term in a fan-made mod or a community discussion, it could be a creative addition by players, but it's not part of the base game. For the most accurate information regarding all official aspects of "Plants vs. Zombies," it's best to check directly with the game's developers or official sources.