Consequences, you say.

That doesn't sound very Buddhist-like to me; Buddhist doctrine focuses on altruism.

I can't think of anything within Chinese folk religion that's even remotely similar, sorry.

actually all "buddism" or "deity" have their own version in their own country. For example, gautama, bhaisajyaguru, amitabha, they are the "most commonly" known buddha all over the world. However, each country has their own interpretation and their own way of worshipping but not very far off from each other. I take bhaisajyaguru for example. In Japan there is a dedicated temple called yakushi-ji. In Japan, bhaisajyaguru is called yakushi. In china, "yao shi fuo" (藥師佛）。 In thailand, Phra Kring. In tibet, bhaisajyaguru. I believe you might be talking of something similar.

However, please be aware that Japan is very "tradisional" and they do worship "natural" local deity like the 9 tail fox and so on. Its like the Japan verson of chinese folklore. Ie, it was a "local adaptation" of buddism plus taoism in their own culture sense and the buddha you mention might not really be a "buddha". The only one i can think of is the "brahman" or the 4-face buddha (Erawan) in the thailand version. I am sure you heard of the 4 face buddha in thailand where you make a wish/desire and when what you wished for came true, you need to give something back (what you promised when you make the wish) or whatever you seek will be gone and with some consequences? In japan I will not be surprised if such version (in their own local adaptaion) existed.
actually, i believe there is "the 3 wise man" in chinese folklore whom i believe that sounds like the brahman. And i think there is similar stuff where you make a wish in exchange for something you will give (exchange) when you get what you asked for. Isnt there one?

Ah, then I can tell you what natch said is correct. It is not the "main stream" buddism. It sounds more like the local adaptation of japanese buddism/local deity/culture type. In Japan, besides the "main" buddhas, they have different sects or schools (like any country) as well that practices slightly different. I believe your friend had mess with the "bad" side of the practice. In thailand, there is one that is called kumanthong. Normally I do not wish to mention so ppl will not ask more of it. Its known as small ghost or little ghost in chinese. In japan, there is also a sect of schools/culture that "welcomes" it. It is called Zashiki-warashi. I am not sure if your "friend" is talking about these but its a small boy or girl version which you can "invite" by performing certain ceremony and it sorts of follow you around. It comes and goes as they like. But i can tell you that you are not talking about the same thing from the two different post as the first post you mention a buddha (a buddha dont do these wish thingy to be honest) and on the second post you mention it "sticks" to you. There are quite a number of yokai (spirits) that can stick to a person in Japan's cultural believes. It is definitely out of this scope in these thread and before you anger our local "guardian" of the page, mr Natch, I believe we should not discuss this topic further. I am very scared of mr Natch's holy "smite" since he is experts in needles, injections and diseccting human alive..............

I don't mind the occasional ghost story.

A good number of the Hell deities are ghosts, after all, so it would not be entirely off-topic to discuss ghosts here.

Probably so as not to frighten the public.

Most people have the misconception that Hell deities are scary creatures of ill omen.