It appeared to be caught! catching Pokemon?

Random chance.

Each species of Pokémon has a catch rate, a number out of a maximum of 255, that applies to all its members. When a Poké Ball is thrown at a wild Pokémon, the game uses a formula based on its current health, any status effect it may have, and that Pokémon's catch rate, to determine the chances of catching that Pokémon.

Approximately, the probability of catching a Pokémon starts with the species' catch rate divided by 255. Then it is multiplied by the following factors:

The health of the Pokémon (relative to its full health), which can reduce the probability to ⅓× at full health.

The type of Poké Ball, which can augment by some ×.

The status of the wild Pokémon, i.e. 2× increase for sleep or freeze, and 1.5× for others.

The effects stack multiplicatively — for example, a 2× and a 3× will combine to be 6×. If the calculation ends up greater than 1, the wild Pokémon is assured to be caught.

The rarity of the Pokémon (i.e. how often it appears in the wild) is totally independent from its catch rate after it is encountered. Even rare Pokémon may have high catch rates, making them relatively easy to catch in battle, such as Nosepass (catch rate 255).

The game uses complex algebra to decide whether or not to catch a pokemon. It all depends on the ball you use, if it has a status problem and how much HP it has left. The formula for determining the capture of the Pokémon is as follows: Catch = PokeballEffect (((( 4 Max HP - 2 HP ) * Catch Rate ) / Max HP ) + Status + 1 ) / 256 Now the Maximum HP and Current HP of the Pokémon that you are about to catch are obviously not known by you, however that is what the colour coding is for and really the lower the level the better the chance. If however the HPs are over 255, then they are divided by 2 and then by 2 again and placed into the equation as such once rounded down to the nearest digit. Status Ailments are a completely different amount however. Here is a small table stating the Values that each of the Status Ailments is given Status Figure Frozen 10 Sleep 10 Paralysis 5 Burn 5 Poison 5 None 0 Now this does have a major effect on the capture and could definately be the difference between capturing the Pokémon. The final element of capturing Pokémon is the type of Pokéball that is used. Each of the Pokéballs either Multiply or add to the figure before the final division of 256 is done in order to determine the final amount.

A Wild Pokemon Appears

Ultraball? Lvl 3 pokemon? What a waste.

If you can't catch a Lvl 3 pokemon with an ultraball then you're just plain unlucky. You can usually catch those at full health with a great ball.

Catching pokemon with pokeballs is always strange and weird. While Ultra Balls are more likely, if you just don't have the luck with them, then use a different kind. It's more random than another else.

Ultra Balls only work on Advanced Pokemon. A Pokeball or a Heal Ball, (For when it has a status problem) would work on weaker Pokemon.

I don't know, it's quite crazy...My cousin always says pokeballs are his favourite because they work best for him, even though ultra balls are meant to be so much better!

Bad luck.