Hey - I dont have much experience with Maractus, but I'd just like to point out a few things. Not QC, just giving my 2 cents.
First off, the formatting of the set is a bit off, but thats understandable for your first time.
What you have should look like this:
Spikes
########
name: Spikes
move 1: Spikes
move 2: Petal Blizzard / Endeavor
move 3: Knock Off
move 4: Sucker Punch / Endeavor
ability: Water Absorb
item: Focus Sash
evs: 252 Atk / 4 Def / 252 Spe
nature: Jolly
In the overview, you should note other spikes users that outclass maractus, as cacturne is more commonly seen as a swords dance user. Garbodor, Qwilfish, Crustle, and Accelgor are good examples to use. I know that its true and all, but saying a Pokemon is adorable is just fluff and shouldnt be in the overview.
When describing moves, dont say that it is why it has a niche over another Pokemon, say something like "Knock Off is a good utility move that cripples defensive Pokemon by removing their item." Same goes for the other sentences in other places comparing stuff to Cacturne, the analysis is supposed to be about that Pokemon, not comparing it to others. You can certainly mention other Pokemon that have the same role, but it shouldnt be that prevalent.
Bastiodon is a bad example of a taunt user, replace it with Mismagius like Dat Blast said. I dont honestly think its relevant enough to have a mention, as its pretty much the only pokemon that uses Magic Coat.
In addition, checks and counters should be formatted like this:
**Taunt Users**: Taunt users such as Qwilfish and Mismagius can prevent Maractus from setting up Spikes, but Mismagius doesnt appreciate Knock Off.
Damage calcs are also fluff and should be removed, there is no need to mention it in an analysis.