The best advice I can give for fighting Dedede is that when you're being chaingrabbed you should be smashing up on the c-stick the entire time. This way if the opponent trips or messes up the chaingrab they get an upsmash in the face. Also if you go off an edge, Uair will come out immediately and prevent combos depending on the spacing. Other than that just play smart and get around his side B and you'll be fine.
If the DDD player is prone to d-throwing and watching the reaction of players afterwards, this could get you f-smashed on reaction by the DDD.
(really haven't liked posting in these forums lately but I think I can help out here) There's a much easier way to beat DDD. B-stick for the matchup. I'm sure half the people reading this post are already moving on to the next one but if you want an easier time, hear me out. When Lucas is approaching, his anti-shieldgrab game is amazing, yes. However for everytime you hit that DDD with an ftilt, he's not thinking "**** I better stop grabbing and do something else". He's thinking "Can't wait till he messes up once/guesses wrong so I can give him 24%~+ and edgeguard =D". And as we all know, off the stage Lucas is "his own version of low tier". Taking a sweetspot bair from DDD during the point in your PK thunder where you have to di down and away (ouch...) is usually going to lead to your stock being taken at nearly any percent.
B-sticking is one of the projectiles that DDD can't just plow into for a grab. Even if he runs in, powershields the fire, and runs in for a grab, he won't catch you before you can react. What this means is that b-sticking Lucases are forcing DDD to make an approach where he actually has to make a guess and put himself into unsafe situations. With the normal pk fire, he's going to run in, block the fire, and take you across the stage for thinking you can camp him like that.
Don't get me wrong though. B-sticking isn't anywhere near a free win but it does put the match on a level playing field and this is coming from the guy that plays with the best DDD in Florida.
Other tips: When edgeguarding with PK Thunder, be aware of the situation. If the DDD is below the stage recovering somewhat close to the stage, don't PK Thunder. On reaction, the DDD can up-b, super armor your pk thunder and hit you with his up-b before you have any chance of defending yourself due to the 3-second duration of your pk thunder and it not being fast enough to catch DDD's up-b. If he's far enough away that he couldn't make it with just up-b, yes PK Thunder him. If he's above the stage and a decent distance away, yes pk thunder him because then he'd have to up-b high and you could probably catch him on his descent if you predict correctly. If he's not in a PK Thunder situation, go out there and get him. You should have no fear in this. Go out there and get shameless. Fair him, if he airdodges, double jump dair. Even if you miss both, you'll probably still get back to the stage faster and safer than he will.
He should be scared everytime he knows he's not making it back to the stage with just one or two jumps. And for all that is good, up-smash his up-b if he tries to land on the stage. Even if he cancels it, the weak part will still hit him and leave him in the air with (probably) no jumps. If he doesn't cancel it (which he probably won't since he's DDD, you're Lucas and he has no respect for your character), you'll kill him at like 90. Personally, I love seeing DDD die at that number.
Finally, please don't be ******** in the matchup. If DDD is coming in from really high, don't stand at the edge of the stage like a dumb**** charging up smash. He's gonna fast fall, suck you off the stage, you're gonna die and be depressed. If he's charging a side smash on the stage as you're grabbing the edge, the correct answer is not to jump onto the stage and try to airdodge through him. The correct answer is not to stand up or jump. Just don't **** with it. Wait for it to be done or if he's really close cause he's bad, getup attack him and beat his smash with your invincibility. Don't get off the same way from the edge every time. If you jump dair from the ledge everytime, you're gonna get up tilted eventually.
Now then, have some fun facts.
Fun facts:
-You can absorb the stars (with perfect spacing) from his up-b but... why? If you wanna be fancy, go for it. If you have tap jump on, I'm pretty sure you can cancel your down-b after absorbing the stars with up-smash or up-b. Otherwise, drop it and run up to throw him back off/fair him back off.
-Your d-smash will beat his Inhale if he's drawing you in, the bat too, I think but the d-smash definitely.
-You can absorb the beam from his Waddle Doo for heavy healing and roll out as he approaches. I have been hit on rare occasions by the beam as I tried to roll out so watch out for that.
Like I said, I don't like posting in these forums lately so Iunno if I will again for a bit but I'll try to be helpful. G'luck y'all.