Starfox
Hero
I used to play a lot of Planescape, but we used a homebrew system, not DnD in any form. Planescape has a LOT of weird critters, and the player often had advisers that were quite knowledgeable. One way to represent this was to hand out the 2E monstrous compenium page. The player knew what the critter was like in 2E, but had no idea of what the conversion was like!