large sudden profiler spike

Hi i have virtually no experience with t$$anonymous$$s. my game runs fine for a good w$$anonymous$$le running 60fps but no matter where i go or what i do it eventually has t$$anonymous$$s massive spike in rendering and physics and the game becomes unplayable.

is t$$anonymous$$s garbage collection as people have said? I see there is a garbage collection aspect to the graph but it appears to be rendering and physics instead. how can i fix t$$anonymous$$s? Just basic pointers if you can.. please don't use game dev jargon or acronyms too much thanks.