Seriously folks. This post only proves that very few people understand how spells work. Within the realm of magick, any spell can work, and any spell can fail.
Even tested spells will fail if the person casting them does not understand how to apply their will and energy to them.
ALSO!!! Even spells made up for fantasy can work if the person casting them DOES know how to apply will and energy.
Obviously no one will be transforming into a mermaid anytime soon... the idea of recording a spell on a video to "prove" that it works is absolute rubbish. Spells never work that way. Usually even when a spell is working, there is NO obvious physical reaction that can be recorded.
If you learn how spells work, the best way to make sure you have a "good" spell is to write it yourself. The spell is simply a tool to help you put your energy to use. A mechanic can use a toy wrench OR a real wrench...it's just that the real one works better. Spells are like magickal wrenches. You don't need them, they just make it easier to use the power you have. Technically, if you're strong enough you don't NEED a wrench for anything. The same is true about spells.
Most people are not that strong...so we make spells, and wrenches to help us out.
I hope my analogy is understood here. This concept is one of the biggest stumbling blocks in magick. Don't think of it as spells that "work" or "don't work". Look at any spell and ask yourself "Can I make it work?" If the answer is "no" then you don't know enough to cast it, even if the spell is genuine.