You get to imbue one species with human level intelligence and retire to a safe vantage point to observe the results.
What do you pick?
Not much, really. They could make a surprise attack on beaches worldwide and severely hurt/kill a bunch of people, but after humans are onto their game their physical capabilities are so limited that there isn't much else to do.
It's not like any animals are gonna start building civilizations, etc even if they have intelligence, too many animal impulses and traits. Eg. nignogs, humans but cannot do anything