You don't have to give this person anything to prove you care. But maybe you want to; it's an easy way of letting them know your affection and telling them you're open to a relationship. If you're already with your love interest, a gift might just remind them of your feelings. Most would give flowers or chocolate or offer up a night of quality time or chores done. Those are the usual.
You're not usual yourself. Neither is the person you're with...or want to be with. You'll have to go for the unusual.
So whether it's building your crush a robot to ask them out, making your friend-or-possibly-more the best fifteen course meal they've ever had, or teaching your significant other to be the strongest ninja warrior, go big or go home. Or go where it's natural, given how unconventional you can be.