The Mad Cat? Yowlin Yeti Catnip & Silvervine Cat Toy Twin Pack is a super silly plush filled with a unique blend of premium catnip and silvervine that's maximum potency, pure, and pesticide-free. Silvervine is an all-natural catnip alternative that cats love, it elicits a similar reaction to catnip and works for many cats who normally are not affected by catnip. The unique blend of catnip and silvervine tempts kitties to play and cuddle.?Silvervine is a species of kiwifruit that is completely non-toxic and all-natural.?Entices cats who aren't affected by catnip. High-quality plush includes embroidery, crinkle paper, and ropes.