ALL THE OTHER GAMES GANNON ISN'T THAT SCARY

out of that list I'd say OoT and TP.
(also, don't forget Wind Waker, specifically Puppet Ganon)

IT IS THE SCARIEST OF ALL HIS FORMS :0)

Ocarina of Time, hands down. It's got such a dark and foreboding atmosphere.

Oot by far

OoT and TP
TotK was fairly easy and the Demon Dragon design was more cool than scary
BotW could be scary if you're like a first timer but once you figure it out he's just a big yucky hog with a big eye

Oot looks like the scariest next to Twilight princess

Botw and totk are ez

Oot might be scary even though I have not played it

Trust me, it's not fun, it's nerve racking, the entire fight leading up to the final form