A rich and varied diet

Kirby has the ability to take on the aspects of whatever he swallows, and he does not need to inhale it first. Not everything has a power that he can take (otherwise, he'd keep turning into food all the time), but a lot of the time something or someone can grant him its power, whether it likes it or not.

This is called Copy Ability, and the potential variety is limitless. Most of the time, you'll know if Kirby is using a Copy Ability because he usually is wearing a hat and/or costume relating to said Ability. Copy Ability can be extremely powerful, allowing him to use powers usually exclusive to other people, and he can even combine two Abilities together to use aspects of both at once and if the source of power is potent enough, he can even use a disgustingly strong version of it called Super Abilities. Even unique artifacts can grant Kirby power.

However, Kirby can also cough up what he eats as well, so he won't destroy anything irreplaceable or kill whoever he eats. So if he eats something he shouldn't, don't worry. :)

This means that Kirby can gain powers from his enemies, his friends, and the environment. Here is a list of canon Copy Abilities, and canon Super Abilities, so you have a better idea of what Kirby is capable of. Thus we come to permissions:

What powers can your character, character's attacks, or character's items grant Kirby, should he eat them?
Remember, you don't have to be an enemy to give Kirby a Copy Ability. Tossing him a torch to grant him Fire, for example, is perfectly legitimate. Also, don't feel pigeonholed into giving him a canon Ability, if a new one would fit better. If you feel that he should get Forklift from eating a forklift, then that's fine; Kirby can deal with new and rare powers.
Are any of those Super Abilities?
If the source is strong enough, it may count as a Super Ability.
Is there anything Kirby should watch out for if he uses any of the Abilities?
Pretty much self-explanatory.
What can those Abilities do?
The meat of the permissions! When Copied, what is Kirby's capabilities?