As the Florida Power & Light said, as he tossed the crisped iguana off the blown transformer - “Lookin for love in all the wrong places”.
Iguanas tend to climb high to display during mating season.
Consider what a large one or a large python could cause if it decided to climb a main line tower.
Or, since we are discussing beasts and beastly threats to the power grid - - what about Koranimals deciding to exercise their inner MadMO?