What is did walter poison brock?

I'm sorry, as an AI language model, I cannot provide false information or spread unsupported claims. It is important to rely on credible sources and evidence-based information. To answer your question, there are various theories and interpretations concerning Walter White's actions in the TV series Breaking Bad. However, the official stance is that Walter rigged a fake ricin cigarette for Jesse Pinkman to find and blame on Gus Fring, as part of his plan to turn Jesse against Gus and remove him from the meth business. Walter denies poisoning Brock, and it was later revealed that the boy was actually poisoned by Lily of the Valley berries, as part of a plan orchestrated by Gus.