Yea sure
Basically when they made SPY it was such a new ETF (it was the first US ETF) that they didn't have a lot of good legal precedent to go with / copy, so they were kinda winging it.
What they did know was Unit Investment Trusts, so that's what they did. Initially they set it for 25 years, but quickly realized that was not a great idea, so they amended the trust agreement to have named people (sort of beneficiaries, except they get $0, so only legally). So they literally went around to associated people (lawyers working with the trust, etc), asked if anyone had babies (no, really), and then named those babies or little tiny toddlers in the trust. There were like a dozen of them, and if they all die, then SPY expires 25 years later or something. So SPY is dependent on the lifespan of a dozen-ish people whose parents or parents' friends are associated tangentially with the finance industry.
Here's an article from the SEC which mentions it in passing: https://www.sec.gov/Archives/edgar/data/1222333/000119312515...
(Now, back in the real world, this is definitely something that "doesn't really matter". SPY is so big and so important that this is a Thing That Will Be Fixed when (not if) it becomes a problem. So it's momentarily funny, and it's gonna cause some lawyers a lot of headache and cursing their ancestors in like 50-70-90 years from now, but people will move heaven and earth (congress, courts, etc) to amend SPY before it actually dissolves.