Surprise Animal SVG

```svg
<svg viewBox="0 0 800 600" xmlns="http://www.w3.org/2000/svg">
  <defs>
    <!-- Cosmic Background Gradient -->
    <linearGradient id="spaceBg" x1="0%" y1="0%" x2="0%" y2="100%">
      <stop offset="0%" style="stop-color:#0d0221;stop-opacity:1" />
      <stop offset="50%" style="stop-color:#1a0b3c;stop-opacity:1" />
      <stop offset="100%" style="stop-color:#2d1b69;stop-opacity:1" />
    </linearGradient>
    
    <!-- Nebula Clouds -->
    <radialGradient id="nebula1" cx="50%" cy="50%" r="50%">
      <stop offset="0%" style="stop-color:#ff006e;stop-opacity:0.3" />
      <stop offset="100%" style="stop-color:#ff006e;stop-opacity:0" />
    </radialGradient>
    
    <radialGradient id="nebula2" cx="50%" cy="50%" r="50%">
      <stop offset="0%" style="stop-color:#00f5ff;stop-opacity:0.2" />
      <stop offset="100%" style="stop-color:#00f5ff;stop-opacity:0" />
    </radialGradient>
    
    <!-- Turtle Shell Gradient -->
    <linearGradient id="shellGrad" x1="0%" y1="0%" x2="100%" y2="100%">
      <stop offset="0%" style="stop-color:#00d9c0;stop-opacity:1" />
      <stop offset="50%" style="stop-color:#0077b6;stop-opacity:1" />
      <stop offset="100%" style="stop-color:#023e8a;stop-opacity:1" />
    </linearGradient>
    
    <!-- Skin Gradient -->
    <radialGradient id="skinGrad" cx="30%" cy="30%" r="70%">
      <stop offset="0%" style="stop-color:#48cae4;stop-opacity:1" />
      <stop offset="100%" style="stop-color:#023e8a;stop-opacity:1" />
    </radialGradient>
    
    <!-- Bioluminescent Glow -->
    <filter id="glow">
      <feGaussianBlur stdDeviation="3" result="coloredBlur"/>
      <feMerge>
        <feMergeNode in="coloredBlur"/>
        <feMergeNode in="SourceGraphic"/>
      </feMerge>
    </filter>
    
    <!-- Star Twinkle -->
    <filter id="twinkle">
      <feGaussianBlur stdDeviation="0.5" />
    </filter>
  </defs>
  
  <!-- Background -->
  <rect width="800" height="600" fill="url(#spaceBg)" />
  
  <!-- Distant Stars -->
  <g fill="#ffffff" opacity="0.8">
    <circle cx="100" cy="80" r="1.5" opacity="0.6"/>
    <circle cx="250" cy="150" r="1" opacity="0.8"/>
    <circle cx="500" cy="50" r="2" opacity="0.4"/>
    <circle cx="700" cy="120" r="1.5" opacity="0.7"/>
    <circle cx="50" cy="300" r="1" opacity="0.5"/>
    <circle cx="750" cy="400" r="1.8" opacity="0.6"/>
    <circle cx="400" cy="550" r="1.2" opacity="0.9"/>
    <circle cx="150" cy="500" r="1" opacity="0.4"/>
    <circle cx="650" cy="250" r="1.5" opacity="0.5"/>
  </g>
  
  <!-- Nebula Clouds -->
  <ellipse cx="200" cy="200" rx="300" ry="200" fill="url(#nebula1)" opacity="0.6" />
  <ellipse cx="600" cy="400" rx="250" ry="180" fill="url(#nebula2)" opacity="0.5" />
  <ellipse cx="400" cy="100" rx="200" ry="150" fill="#ff00ff" opacity="0.1" />
  
  <!-- Distant Planet -->
  <circle cx="650" cy="100" r="40" fill="#ff9e00" opacity="0.8">
    <animate attributeName="opacity" values="0.8;0.6;0.8" dur="5s" repeatCount="indefinite" />
  </circle>
  <circle cx="650" cy="100" r="40" fill="url(#nebula2)" opacity="0.3" />
  
  <!-- Cosmic Sea Turtle -->
  <g transform="translate(400, 300)">
    <!-- Back Flippers -->
    <path d="M-60 80 Q-90 120 -80 140 Q-60 130 -40 100 Z" fill="url(#skinGrad)" opacity="0.8" />
    <path d="M60 80 Q90 120 80 140 Q60 130 40 100 Z" fill="url(#skinGrad)" opacity="0.8" />
    
    <!-- Tail -->
    <path d="M0 90 Q-5 120 0 140 Q5 120 0 90" fill="#0077b6" />
    
    <!-- Front Flippers -->
    <path d="M-50 20 Q-120 0 -140 30 Q-100 60 -50 40 Z" fill="url(#skinGrad)" filter="url(#glow)" opacity="0.9">
      <animateTransform attributeName="transform" type="rotate" values="-5 -50 30;5 -50 30;-5 -50 30" dur="4s" repeatCount="indefinite" />
    </path>
    <path d="M50 20 Q120 0 140 30 Q100 60 50 40 Z" fill="url(#skinGrad)" filter="url(#glow)" opacity="0.9">
      <animateTransform attributeName="transform" type="rotate" values="5 50 30;-5 50 30;5 50 30" dur="4s" repeatCount="indefinite" />
    </path>
    
    <!-- Shell Base -->
    <ellipse cx="0" cy="40" rx="70" ry="85" fill="url(#shellGrad)" stroke="#00f5ff" stroke-width="2" opacity="0.9" />
    
    <!-- Shell Pattern (Hexagonal Scutes) -->
    <g fill="none" stroke="#00f5ff" stroke-width="1.5" opacity="0.6">
      <!-- Center -->
      <path d="M-15 40 L-7 26 L7 26 L15 40 L7 54 L-7 54 Z" fill="#00d9c0" opacity="0.3" />
      <!-- Surrounding -->
      <path d="M-15 40 L-30 35 L-30 50 L-15 55 Z" fill="#0096c7" opacity="0.2" />
      <path d="M15 40 L30 35 L30 50 L15 55 Z" fill="#0096c7" opacity="0.2" />
      <path d="M-7 26 L-20 15 L-5 10 L7 26 Z" fill="#0096c7" opacity="0.2" />
      <path d="M7 26 L20 15 L5 10 L-7 26 Z" fill="#0096c7" opacity="0.2" />
      <path d="M-7 54 L-20 65 L-5 70 L7 54 Z" fill="#0096c7" opacity="0.2" />
      <path d="M7 54 L20 65 L5 70 L7 54 Z" fill="#0096c7" opacity="0.2" />
      <!-- Outer ring -->
      <path d="M-30 35 L-45 25 L-50 40 L-30 50 Z" fill="#0077b6" opacity="0.2" />
      <path d="M30 35 L45 25 L50 40 L30 50 Z" fill="#0077b6" opacity="0.2" />
      <path d="M-20 15 L-25 0 L-5 10 Z" fill="#0077b6" opacity="0.2" />
      <path d="M20 15 L25 0 L5 10 Z" fill="#0077b6" opacity="0.2" />
      <path d="M-20 65 L-25 80 L-5 70 Z" fill="#0077b6" opacity="0.2" />
      <path d="M20 65 L25 80 L5 70 Z" fill="#0077b6" opacity="0.2" />
    </g>
    
    <!-- Shell Glow Lines -->
    <path d="M0 10 L0 70 M-35 25 L35 55 M-35 55 L35 25" stroke="#00f5ff" stroke