What's the hardest legendary for you to catch? Personally for me, it would be Moltres. That bird would not stay in the pokeball. -_- I have to restart it a couple of times because I ran out of ultra balls. I didn't have to battle Mewtwo since I used a masterball on him. Suicune on the other hand, it took me awhile to track it down but I manage to prevent from running away with mean look. At least it took me about 10 ultra balls to catch that beast.

Zapdos was the easiest one to catch. It took me just 2 ultra balls to cach it without putting any status. I caught Articuno after putting it to sleep and threw about 8 ultra balls.

Mewtwo was exceptionally hard. It took me a lot of Ultra balls to catch it, not to mention the number of times I restarted. It was pure evil.

Kyogre, purely because I let my friend battle kyogre, thinking that if he fainted it I'd just restart and continue just before the battle as my amigo would have saved it like I told him to.

Of course he forgot to save it and fainted it >_>
I was so upset I did a whole new game afterwards to get that slimy fish ¦D

1st gen though (to fit with the title) I'd have to say mewtwo. The little birds weren't too hard at all.

In Gen. I you had to inflict a status condition before trying to catch a legendary.

I'd have to say Lati@s. I went for Latios in Emerald, and I couldn't catch it no matter what. Then, I went to the 10th Anniversary event, and got one for free. I found the original, and caught it with a Repeat Ball .

I'd have to say those beasts. They'd run around time to time with a small catch rate and you only have one shot.

Mewtwo and the birds weren't to hard wasn't very hard for me tbh.

Articuno always gave me a challenge

Despite technically being no more difficult to catch, Articuno always seems to be tougher to catch than all other legendaries. I have no idea why, but I always spend far longer in those bloody caves than Victory Road or the Power Plant or Cerulean Cave. I've never tried to catch the dogs (Also, that's third gen).

Articuno. I'll admit I had a hard time catching it, as I kept either killing it or running out of different kinds of Pokéballs.

Gonna have to say Moltres on this one. For some reason, it made me soft reset many times where Zapdos was caught easily and Articuno was caught in a great ball (in Fire Red anyway).