Things Gustavo is a little bit afraid of and will make him run away:
Hand lotion
Flies
Butterflies
Umbrellas
Tarps
Horses wearing fly masks
Campers in the forest
Big dogs that touch him lightly with their paw
The big train
Lighting the stove
Pumpkins in the wrong place
Rocks in the wrong place
Boxes left out in the street that weren’t there before
Trees at odd angles in the forest
The vacuum
Loudspeakers next to him that say “Go” in a robot voice
This list could go on and on and on…

Things that scare Gustavo more and make him nervous and shake:
Sheetrocking
Power tools
Cigarettes
Lighters
Matches
Campfires
Bonfires
Birthday candles
Regular candles
Lighting pretty much anything on fire
Longe whips snapping

Things that scare Gustavo so much he goes into catatonic state:
Gunshots, even if they’re fake ones by civil war re-enactors
Fireworks that go BOOM