diff --git a/th01/main/boss/b20m.cpp b/th01/main/boss/b20m.cpp
index 655ab9e2..4e3bf616 100644
--- a/th01/main/boss/b20m.cpp
+++ b/th01/main/boss/b20m.cpp
@@ -108,6 +108,7 @@ extern union {
 	int speed_multiplied_by_8;
 	int interval;
 	int start_frame;
+	pixel_t velocity_x;
 	int unknown;
 } pattern_state;
 extern bool16 invincible;
@@ -2284,3 +2285,88 @@ void pascal near particles2x2_horizontal_unput_update_render(int frame)
 	#undef left
 	#undef col
 }
+
+struct CurvedSpray {
+	screen_point_t target;
+	Subpixel speed;
+	unsigned char angle; // should be local
+	int subpattern_id; // controlled by the pattern
+
+	void init(void) {
+		target.x = PLAYFIELD_LEFT;
+		target.y = PLAYFIELD_BOTTOM;
+		speed.set(7.0f);
+		subpattern_id = 0;
+
+		// Divisor = number of pellets effectively fired per direction.
+		select_for_rank(pattern_state.velocity_x,
+			(PLAYFIELD_W / 20),
+			(PLAYFIELD_W / 26.66),
+			(PLAYFIELD_W / 35.55),
+			(PLAYFIELD_W / 40)
+		);
+	}
+
+	void fire_and_advance(x_direction_t dir) {
+		angle = iatan2((target.y - SEAL_CENTER_Y), (target.x - SEAL_CENTER_X));
+		Pellets.add_single(SEAL_CENTER_X, SEAL_CENTER_Y, angle, speed);
+		speed -= 0.25f;
+		if(dir == X_RIGHT) {
+			target.x += pattern_state.velocity_x;
+		} else {
+			target.x -= pattern_state.velocity_x;
+		}
+	}
+
+	void reset(screen_x_t new_target) {
+		speed.set(7.0f);
+		target.x = new_target;
+	}
+};
+
+void pascal near pattern_curved_spray_leftright_once(int &frame)
+{
+	#define spray	pattern12_spray
+
+	extern CurvedSpray spray;
+
+	if(frame < 50) {
+		return;
+	} else if(frame == 50) {
+		dottedcircle_unput_update_render(
+			SEAL_CENTER_X, SEAL_CENTER_Y, 1, 4, 16, V_WHITE, 32, 160
+		);
+	}
+
+	// The duration can be calculated as:
+	//
+	//	target_radius = √((RES_X - SEAL_CENTER_X)² + (RES_Y - SEAL_CENTER_Y)²)
+	//	duration = (((target_radius - radius_initial) / radius_step) * interval)
+	//
+	// Good luck doing that at compile time, but given the variables defined
+	// here, the result does come out as 88.38. So, close enough.
+	dottedcircle_unput_update_render(
+		SEAL_CENTER_X, SEAL_CENTER_Y, ((frame - 50) + 1), 4, 16, V_WHITE, 32, 90
+	);
+
+	if(frame < 100) {
+		return;
+	} else if(frame == 100) {
+		spray.init();
+	}
+
+	if(spray.subpattern_id == 0) {
+		spray.fire_and_advance(X_RIGHT);
+		if(spray.target.x >= PLAYFIELD_RIGHT) {
+			spray.subpattern_id = 1;
+			spray.reset(PLAYFIELD_RIGHT);
+		}
+	} else {
+		spray.fire_and_advance(X_LEFT);
+		if(spray.target.x < PLAYFIELD_LEFT) {
+			frame = 0;
+		}
+	}
+
+	#undef spray
+}
diff --git a/th01_reiiden.asm b/th01_reiiden.asm
index 75e1cd70..3a2344ec 100644
--- a/th01_reiiden.asm
+++ b/th01_reiiden.asm
@@ -22450,10 +22450,10 @@ main_36_TEXT	segment	byte public 'CODE' use16
 	@pattern_symmetric_birds_from_bot$qv procdesc near
 	@pattern_four_semicircle_spreads$qv procdesc near
 	@pattern_vertical_stacks_from_bot$qv procdesc near
-	@DOTTEDCIRCLE_UNPUT_UPDATE_RENDER$QIIIIIIII procdesc pascal near \
-		center:dword, frame_interval:dword, radius_step_col:dword, radius_initial_duration:dword
 	@PARTICLES2X2_HORIZONTAL_UNPUT_UP$QI procdesc pascal near \
 		frame:word
+	@PATTERN_CURVED_SPRAY_LEFTRIGHT_O$QMI procdesc pascal near \
+		frame_seg:word, frame_off:word
 main_36_TEXT	ends
 
 main_36__TEXT	segment	byte public 'CODE' use16
@@ -22465,94 +22465,6 @@ include th01/main/boss/anim.inc
 
 sariel_shield	equ <boss_entity_0>
 
-; =============== S U B	R O U T	I N E =======================================
-
-; Attributes: bp-based frame
-
-sub_2B6EA	proc near
-
-arg_0		= dword	ptr  4
-
-		push	bp
-		mov	bp, sp
-		les	bx, [bp+arg_0]
-		cmp	word ptr es:[bx], 32h ;	'2'
-		jl	loc_2B838
-		les	bx, [bp+arg_0]
-		cmp	word ptr es:[bx], 32h ;	'2'
-		jnz	short loc_2B71C
-		call	@dottedcircle_unput_update_render$qiiiiiiii pascal, large (320 shl 16) or 185, large (1 shl 16) or 4, large (16 shl 16) or 7, large (32 shl 16) or 160
-
-loc_2B71C:
-		push	(320 shl 16) or 185	; (center_x) or (center_y)
-		les	bx, [bp+arg_0]
-		mov	ax, es:[bx]
-		add	ax, -49
-		push	ax	; frame_1based
-		push	(4 shl 16) or 16	; (interval) or (radius_step)
-		push	(7 shl 16) or 32	; (col) or (radius_initial)
-		push	90	; duration
-		call	@dottedcircle_unput_update_render$qiiiiiiii
-		les	bx, [bp+arg_0]
-		cmp	word ptr es:[bx], 64h ;	'd'
-		jl	loc_2B838
-		les	bx, [bp+arg_0]
-		cmp	word ptr es:[bx], 64h ;	'd'
-		jnz	short loc_2B780
-		mov	x_3B327, 0
-		mov	y_3B329, PLAYFIELD_BOTTOM
-		mov	speed_3B32B, (7 shl 4)
-		mov	word_3B32E, 0
-		call	@sariel_select_for_rank$qmiiiii c, offset _sariel_pattern_state, ds, large 32 or (24 shl 16), large 18 or (16 shl 16)
-
-loc_2B780:
-		cmp	word_3B32E, 0
-		jnz	short loc_2B7E7
-		mov	ax, y_3B329
-		add	ax, -185
-		push	ax
-		mov	ax, x_3B327
-		add	ax, -320
-		push	ax
-		call	iatan2
-		mov	angle_3B32D, al
-		call	@CPellets@add_single$qiiuci15pellet_motion_tiii c, offset _Pellets, ds, large 320 or (185 shl 16), word ptr angle_3B32D, speed_3B32B, large PM_NORMAL or (0 shl 16), large 0 or (0 shl 16)
-		sub	speed_3B32B, 4
-		mov	ax, _sariel_pattern_state
-		add	x_3B327, ax
-		cmp	x_3B327, PLAYFIELD_RIGHT
-		jl	short loc_2B838
-		mov	word_3B32E, 1
-		mov	speed_3B32B, (7 shl 4)
-		mov	x_3B327, PLAYFIELD_RIGHT
-		pop	bp
-		retn	4
-; ---------------------------------------------------------------------------
-
-loc_2B7E7:
-		mov	ax, y_3B329
-		add	ax, -185
-		push	ax
-		mov	ax, x_3B327
-		add	ax, -320
-		push	ax
-		call	iatan2
-		mov	angle_3B32D, al
-		call	@CPellets@add_single$qiiuci15pellet_motion_tiii c, offset _Pellets, ds, large 320 or (185 shl 16), word ptr angle_3B32D, speed_3B32B, large PM_NORMAL or (0 shl 16), large 0 or (0 shl 16)
-		sub	speed_3B32B, 4
-		mov	ax, _sariel_pattern_state
-		sub	x_3B327, ax
-		cmp	x_3B327, 0
-		jge	short loc_2B838
-		les	bx, [bp+arg_0]
-		mov	word ptr es:[bx], 0
-
-loc_2B838:
-		pop	bp
-		retn	4
-sub_2B6EA	endp
-
-
 ; =============== S U B	R O U T	I N E =======================================
 
 ; Attributes: bp-based frame
@@ -24360,9 +24272,7 @@ loc_2CB59:
 		call	sub_2BB46
 
 loc_2CB6A:
-		push	ds
-		push	offset _boss_phase_frame
-		call	sub_2B6EA
+		call	@pattern_curved_spray_leftright_o$qmi pascal, ds, offset _boss_phase_frame
 		jmp	short loc_2CBA4
 ; ---------------------------------------------------------------------------
 
@@ -25779,11 +25689,16 @@ _particles2x2_horizontal_left    	dq PARTICLE2X2_COUNT dup(?)
 _particles2x2_horizontal_top     	dq PARTICLE2X2_COUNT dup(?)
 _particles2x2_horizontal_velocity	dq PARTICLE2X2_COUNT dup(?)
 
-x_3B327	dw ?
-y_3B329	dw ?
-speed_3B32B	dw ?
-angle_3B32D	db ?
-word_3B32E	dw ?
+CurvedSpray struc
+	Point <?>	; target
+	dw ?     	; speed
+	db ?     	; angle
+	dw ?     	; subpattern_id
+CurvedSpray ends
+
+public _pattern12_spray
+_pattern12_spray	CurvedSpray <?>
+
 point_3B330	Point <?>
 grc_image_3B334	dw ?
 word_3B336	dw ?