I don't know if anybody cares, or how many people here like using Pikachu, but I just found that Pikachu has not only one, but TWO chaingrabs that work for basically every character in the game. Dedede is known as the character with a very solid chaingrab right now, but I think people fail to notice Pikachu's chaingrabs, one of which does not move the character whatsoever.
Pikachu's chaingrabs consist of his d-throw and his f-throw. F-throw works on every character, but it varies on whether or not the person will be sent at a higher angle. For Pikachu's f-throw, he puts a character on his back, electrocutes them, and sends them a short distance forward. This allows Pikachu to easily run up and grab again without the character being able to react back, regardless of DI. However, at higher percentages it can prove to be ineffective. For example, if you begin the chaingrab at 50%, a lot of characters can escape the f-throw chaingrab. But, if characters are at a low enough percentage, Pikachu can simply f-throw them all the way across the stage until you run into the edge.
D-throw varies greatly from character to character. For Pikachu's d-throw, I did a few tests with Thulius. I d-throwed Fox to literally 100% nonstop, with him trying to reflector / DI back or whatever. You can go even higher than that if the player DIs back into Pikachu for whatever reason. Needless to say, d-throw chaingrab depends a little on whether or not the person hits the grab button again at about the exact moment that the animation for the d-throw is over. But d-throw does not work on every character; it doesn't work at all on Peach or Luigi. For big characters like Bowser, it's more effective to use the f-throw chaingrab. Wolf might be an exception to the d-throw chaingrab. I've tried it with him, and for some reason, he is able to get his reflector out sooner than Fox's, and thus can escape it at like 20-30%.
For characters that can't be d-throw chaingrabbed, they can be f-throw chaingrabbed. This applies to every character in the game. Some characters like Marth can be both f-throw chaingrabbed and d-throw chaingrabbed, it just all depends on their weight/relative size.
A lot of the chaingrab possibilities also depend on how early you begin the chaingrab. If you begin it at 0%, that is the perfect time to do so; the d-throw, for example, will have less knockback due to stale move negation, causing Pikachu to chaingrab to a high % because the d-throw reaches low power after a while.
When the d-throw chaingrab quits working, you can simply follow it up with u-airs (generally 2 can hit your opponent), or possibly a u-tilt, which is what I used to do before I even realized it could chaingrab. You could probably even do a d-smash.
Anyway, what do you guys think? Very useful stuff for one of the most annoying characters in the game. Pikachu's just insane in this game. If any of you find this information to be incorrect, feel free to prove so, but I've been messing with it for the past 2 hours, so I'm pretty sure.
Also, random fact: Falco's d-throw chaingrabs, and Wario's d-throw chaingrabs fairly well, especially for characters like Bowser where all Wario has to do is turn around and grab him again.