Grumpy Cat Glow Pen - Specialty Multi-Color Light Pen Grumpy Cat Glow Pen - Specialty Multi-Color Light Pen. Specialy multi-color light pen featuring Grumpy Cat. Easy to use button activated. Premium pen with clip, 1.0 mm line and black ink. Perfect as Grumpy Cat school supplies, party supplies, party favors, stocking stuffers and more. Officially licensed Grumpy Cat office supplies and merchandise. A great addition to any Grumpy Cat calendar or planner gift.