True, but this was inspired by Doctor Who and if you ever plan to run something similar to that, cheesy, over-the-top plans and spells like this are the bread and butter of the campaign. Well, that and you need important rules for when the PCs destroy the thing/take it over/build their own (because this is D&D and that will happen.) Aside from that, this could just be one of those weird magical things that people might know about but rarely does anyone witness firsthand. Like owlbears. Or oozes. Or watching Mechanus go to war in Beserker Mecha mode. Technically, they're all possible/exist (except maybe that last one) but you may never see them.
And if that doesn't work for you, just fall back on the I-did-it-for-fun! explanation.
How the best Wishes are made. I will add a proviso stating that DMs should be careful when using this. Causality can be a bitch and a half to have to retcon.