(I have since learned that this is known as a "lopper". The round thing is known as a "tennis ball" 😉 included for size comparison.)
As I thought about it later, I wondered if I should have said "scissors-thing" instead of "scissors-things". This is colloquial usage to begin with, so there may not be a correct way to say something incorrectly. Non-colloquially, it probably should have been, "my scissors-like thing". Thus I'm thinking "my scissors thing" would have been better. Is there some sort of rule that would handle colloquial usage of this sort when dealing with singular-plural items such as scissors or pants.