What episode was it with Goku and the needle?

You're likely thinking of the episode where Goku is injured by a poisoned needle. This happens in the Dragon Ball Z anime, specifically in the "The Saiyans Arrive" saga, during the "Goku's Injury" episode.

Here's a breakdown:

* Episode: Dragon Ball Z Episode 29, "Goku's Injury"

* Arc: The Saiyans Arrive

* Context: Vegeta and Nappa arrive on Earth and attack. Goku, weakened from his fight with Raditz, is unable to fight at his full strength. He is injured by a poisoned needle thrown by Nappa, which weakens him further.

Let me know if you have any other questions!