Raphael No Movement Explained

7E105F: Raphael's AI state. Governs his behavior.
7E1060: Raphael's personal "timer". Each state of his AI initializes this timer with a value, and it will count down to 0; once 0 is reached, he switches to a new state.
701970: RNG address used by Raphael

At the beginning, his states will follow this sequence:
beginning cutscene:
00, 01, 02, 03, 04
about to gain control of yoshi, he does a few more things:
06 - stomping down on moon
07 - turning around a few times to choose a direction
08 - preparing to move
05 - moving

You need to pinpoint the VERY LAST frame of state 08, just BEFORE he goes into 05. You can gauge this by looking at the addresses provided above, namely when the state is 08 and the timer becomes 00, that will be the frame you need.

On this frame, you need the RNG value (address provided above) to be either 7F or FF. In either case, what happens is the following:

; $0F/B5BA A5 10       LDA $10    [$00:0010]   ; \
; $0F/B5BC 29 7F       AND #$7F                ;  | rng timer value for
; $0F/B5BE 69 80       ADC #$80                ;  | how long to move
; $0F/B5C0 8D 60 10    STA $1060  [$00:1060]   ; /

Since they didn't clear the carry bit here (it's always set at this point in my testing), you effectively will get $7F + $80 + 1, which is $00.

With a movement time of $00, guess what happens? He doesn't move. Hit away.

Because the value needs to be either $7F or $FF, the chances of this occurring are 1/128, or 0.78125% (perhaps more or less depending on how "good" the RNG is in the game).