List of Super Mario World 2: Yoshi's Island beta elements
From the Super Mario Wiki
This is a list of beta elements for the game Super Mario World 2: Yoshi's Island.
Nintendo marketing department initially pressured Shigeru Miyamoto to have the game use prerendered 3D sprites similar to Donkey Kong Country. The 3D models of Baby Mario and Yoshi used in the introduction might be leftovers of this period of development.
Several sprites from Super Mario All-Stars are present in the final release's code. These include Tweeters, a Super Mario All-Stars Shy Guy and Bob-ombs using the wrong palette. There is also a frowning, rock-like block present in the game's coding, and, perhaps even more oddly, a hulking, barrel-throwing, tie-clad Ukiki that seems to deliberately resemble Donkey Kong. There is also a Biting Bullet Bill that is fully functional but is unused. Finally, there is a Yoshi Egg frame never seen elsewhere. When viewed the Japanese version in ROM form, there also unused Mini-Battles sprites, such as a Shy Guy, a shiny sphere, Baby Mario (this originally want Baby Mario to Watch Yoshi in Mini-Battles), and obviously, a Bandit's face in a shocking expression (originally meant to be using facial expressions on the Bandit, as used when Bandit loses in the Throwing Balloons Mini-Battles.). There is also three unused Mini-Battles. IF you have the PAR (Pro Action Replay) codes the tree is playable, but freezes the game, and so is the mushroom, but you become a Blank Yoshi.