https://www.reddit.com/r/godot/comments/g7xh6w/code_shared_in_comments_creepy_shader_with/

toxic.shader

shader_type canvas_item;

uniform sampler2D noise_tex;
// set the colors in shader params
uniform vec4 color_blend : hint_color;
uniform vec4 color_blend_2 : hint_color;
uniform float PI = 3.1415;

void fragment(){
	vec2 move = vec2(sin(TIME + UV.y * PI) * 0.001, TIME * 0.01);
// remove \"move\" if needed, it scrolls the noise up
	vec4 noise = texture(noise_tex, UV + move);
	
// noise is white so any channel works fine 
	noise.r = pow(noise.r, 3);
// I used NoiseTexture of 512x512
// see the params for noise there
	
	float t = smoothstep(0.04, 0.3, noise.r);
	float t_2 = smoothstep(0.01, 0.2, noise.r);
	
	float angle = PI/2. + (noise.r + TIME * 0.1) * PI;
	
	vec2 dir = vec2(cos(angle), sin(angle));
	
	vec4 col = texture(TEXTURE, UV + dir * 0.04 * t);
	vec4 col_base = texture(TEXTURE, UV);
	
	col.rgb = color_blend.rgb;
	
//  optional lightening
//	col.rgb += pow(t, 7) * 0.5;
	
	col_base.rgb = color_blend_2.rgb;
	
//  optional lightening
	col_base.rgb += 0.2;
	
//  optional darkening
//	col.rgb *= clamp(t_2 - 0.2, 0, 1.);
	
	float d = dot(col, col_base);
	
// 	a bit more pronounced edges
//	COLOR = mix(col_2, col , t);
	COLOR = mix(col_base, col , t_2);
	
}