This smells like a student prank, but I'm interpreting your description to mean:
If that's actually happening I'd be curious which version of iOS is on the iPad, and if it's and older version, does the problem go away in iOS 12.2.
From what I've seen it just kills the app and does not delete it. I could not get it to happen on iOS 12.2, only iOS 12.1.2. That said, my experience could be different then yours. https://usa.kaspersky.com/blog/iphone-hyphen/17217/
this is so confusing.
the first commenter was a little over the top, though - you did clearly state iPads, and he was asking if it was for macOS or iOS. overkill, but i understand his desire for more detailed info. @denice.clapper your following up, after more research, has me picturing kids verbally 'saying into the iPad' (maybe using Siri?) "hyphen 3 times," and all of their apps being deleted. i can't imagine that possibility.
please understand that we all want to help, but it would behoove you to be clear in what you're asking and to give information that helps us understand your environment. i typically do as much research on the front end as possible, because more information is better than not enough. this has helped me get answers in a more timely fashion and has saved time in the back and forth. i sincerely hope this constructive feedback is well received as this is a great community that really does work when everyone works together :)