Create a playful Halloween-themed collage inspired by 1980s retro aesthetics, using vivid watercolor textures and bright pastel colors. Design a series of 8 postage stamp illustrations with wavy scalloped edges arranged in a dynamic grid. Use a fresh, cheerful color palette: bubblegum pink, mint green, electric blue, soft lavender, lemon yellow, and peach. The stamps should feature hand-painted watercolor art with loose brushstrokes and glowing highlights. Include fun and quirky Halloween motifs: A smiling jack-o'-lantern with neon accents and playful swirls. A cute cartoon-style ghost with blushing cheeks. A bubbling cauldron with floating sparkles A black cat with oversized eyes and a fluorescent pink bow A whimsical haunted house with candy-colored windows under a pop-art moon A black spider in a web with rainbow highlights A smiling skull with pastel bones A black bat wearing a purple witch hat with sparkles The words "Trick or Treat" in bold retro typography are at the center top with an oversized watercolor bow in ombré neon shades above the words. The entire image should evoke playful nostalgia, with a touch of 80s pop surrealism, dreamy watercolor blending, and soft glowing outlines