The float thing occurred to me, but like I mentioned in the original post, for testing purposes I changed it to:
Item PV Equal to 2:
- Add attribute "Solid"
- Set pv "Solid" to 1
And "Solid" is indeed set to 1 when it's supposed to, which wouldn't happen if the comparison wasn't working.
Anyway, your suggestion... well, I don't think it can work for what I'm doing. I wanted to keep the description vague, but oh well, here goes.
The item is a hammer that Mario can use in my game. While carrying it around, it's part of his sprite rather than an actual object, but when you get hit by an enemy and shrink to small Mario, it creates a hammer object and drops it to the ground. Small Mario isn't strong enough to use the hammer, so when Mario's health is 1 (meaning he's small), the hammer should be solid. When his health is 2 (Super Mario, and thus strong enough to pick the hammer up again), it shouldn't be solid so he can overlap it and pick it up. I can't use any start of layout things because the hammer is created during run-time, so the only other thing I can think of is adding and removing the solid attribute.