Lakitu has long been an iconic Mario enemy and a staple of the franchise, and the Spiny-throwing menace has apparently been glitched all this time! The sleuths at The Cutting Room Floor dug into the original code for Super Mario Bros. and found that Lakitu’s programming isn’t executing correctly.
The code is written so that Lakitu will throw Spiny eggs at an angle relative to the player’s speed, Lakitu’s speed, the player’s position, and a pseudo-random value. Additionally, the Spiny eggs are supposed to bounce off of any blocks or walls they hit on the way down. Thanks to a bug in the code, this doesn’t happen, and the Spiny eggs thrown by Lakitu drop straight down. You can check out a video showing how Lakitu was supposed to function by clicking above.
Source: The Cutting Room Floor