0:35 gonna make a point here. The rarest main is actually Astro since he’s the only main without a chance up. Brightney gives vee chance up, Mastery toodles gives pebble chance up, and Mastery Tisha gives Shelly chance up. While there is no toon what gives chance up for Astro.
Would it be fun if a toon apeared every 5 floors to play a game of would you rather with positive and negative options? For example, Permenatly removes a machine from the game but chances of twisted pebble will increace. Fun isn't it? His name is Topper. If you reach floor 16 without choosing anything twisted topper will spawn. He cannot move but can shoot a projectile that when a toon hits will get the stuck debuff.
Shelly NEVER spawns to me, I am almost getting all main characters' 100% research (including Dandy) while Shelly is only at 40%!!!!!!!! When she does spawn, I am not using rodger, which are the times I only saw her. I also got pebble recently so grinding ichor wont be a problem :D