another hc that prolly already exists: Norm going through old records about human painting and skin decorating traditions and finding out about jagua, which is like henna, but is made from Jagua fruit/extract, is more long-lasting, and is a blue/navy hue. He finds out that there is a similar plant in Pandora and calls Spider over to test it, not telling him what it is at first. Spider is curious, but as soon as he sees it on his skin, he is hooked. He's asking questions about it, how long it lasts, if he could take some into the woods, how to prepare it by himself, etc. Norm is happy to indulge him in his questions, though he knows a bit less about Pandora's species of pseudo-jagua. After it dries and Norm washes it off, Spider stands in front of the mirror, admiring faint gray waves where he would paint his stripes. Norm told him they'd only get darker as the day went on, and he would feel so excited at the prospect. He wouldn't have to worry about his stripes smudging as he climbs, hops, and runs on branch after branch, and it would last for 2 weeks instead of desperately needing to reapply by midday if there's been a hunt.
Everyone stares. He has a renewed swagger, moving unhindered and not worried about the paint wiping off. The jagua has given him a sense of pride, much like the paint first empowered him. It's a tradition from Earth, as distant as he is from the planet's cultures, combined with something from Pandora. The Omatikaya are in wonder at the shift in routine, for once, seeing Spider without his signature blue paint. As for the Metkayina, Ao'nung especially admires how the water beads on top of the jagua, seeming to magnify the blue, which sits on his skin like waves. The dye deepens in saturation like stormy weather, and they like this change.
What he doesn't know is that the jagua-fruit substitute is a mild Na'vi aphrodisiac.