Where do you live that all three of those things are prominieny enough possibilities to worry about.
Ive got the someond out of their mind on (insert substance) concern here, and bears(and cougars) are numerous outside of the city and occasionally make an an appearance in the urban areas(though probably not enough to worry about)... but as of yet feral hogs are sparse here.
Of course i suppose being nearly or outright impossible never kept me from having nightmares about something. In Louisiana as a 4-5 year old i had nightmares about a Jaguar in the woods behind my house and living in Houston and camping in Texas as a kid it was Grizzlies (briefly Velocaraptors after reading Jurassic Park). Nevermind that i was seperated from the nearest Jaguar by ~1000 miles, Grizzly ~1500 miles, and Raptor by 71million years. Of course these were childhood dreams, not concious worries...