Demo 21 - Electric arc

Shader "Custom/ElectricArc" {
    Properties {
        _MainTex ("Main Texture", 2D) = "white" {}
        _NoiseTex ("Noise Texture", 2D) = "grey" {}
        _Speed ("Speed", Range(0, 50)) = 1
    }
    SubShader {
        Tags { "Queue"="Transparent" "RenderType"="Transparent" }

        CGPROGRAM
        #pragma surface surf Lambert alpha

        sampler2D _MainTex;
        sampler2D _NoiseTex;
        float _Speed;

        struct Input {
            float2 uv_MainTex;
            float2 uv_NoiseTex;
        };

        void surf (Input IN, inout SurfaceOutput o) {
            float time1 = frac(ceil(_Time.y * _Speed) * 0.01);
            float time2 = frac(ceil(_Time.x * _Speed) * 0.01);
            float noise = tex2D(_NoiseTex, float2(time1, time2)).r;
            float2 uv = IN.uv_MainTex;
            uv.y = frac(uv.y + noise);
            half4 color = tex2D (_MainTex, uv);
            o.Albedo = color.rgb;
            o.Alpha = color.a;
        }
        ENDCG
    }
    FallBack "Diffuse"
}