Known Shell Entry Swap Effects

Carryable sprites: resets to state 8 (notably P-switch/key act weird from this)

Flying ? block: hits the block

Bouncing green Parakoopa: changes bounce height (green koopa enters -> low, any other = high)

Powerups: turns into a sprite berry

Baby Yoshi: changes sprite slot being eaten equal to the sprite ID of the Koopa that entered it (i.e. green koopa = slot 0)

Yoshi: changes sprite slot currently in mouth equal to the sprite ID of the Koopa that entered it (must spawn with null sprite)