Rat Reaper
Rattlesnakes are scary creatures.
jaws
roar, rah
roaming soul
gory gorrilla
Lion Lion Lion
Lion, leopard, lava, lightning, leprosy and landslides are scary. They begin with the letter L.
Kreacher (from Harry Potter), knives (when thrown at you...)
a rodent or a rat. maybe the grim Reaper.
Ring.
Rainbow
electric bills ! especially in the middle of an extremely cold winter