Inflation Era

Inflation era is some era after the Big Bang in under one second.

Size
The size itself in the current era which is this one is the size of a marble or maybe the football field, which makes particles hard to move around this era and only in a limited space of the universe itself until today.

Heat
The heat is still immense and tough, it's heat cannot make any weight and all of the stuff, not even humans can survive this problem.

Forces
There is the grand unified force in this period, it ended when the strong force was separated and also the inflation era which created a new era and possibly still the shortest among under one second. The Grand Unified Force may have a stronger froce than all of forces that exist today.