[x] Refine placement of random objects

[amberreeves]

i saw a the very bottom of a random object icon poking out from the very top of the screen. i didn't get a screenshot because it went by so fast, but here is an example of where i saw it. can we refine the placement of these so they always appear in the water?

[mtedeschi]

@jmaj and I talked about this and we're having trouble replicating it. If we see it again, we'll see about trying to resolve it.