Can we just drop the subject with the Yu-Gi-Oh! cards?!
Okay... Enough of this.
The signs have been there, and now I'm calling them out. You're coming off as a bit of a control freak with this thread. At least in my eyes.
The Yugioh thing is still technically on topic. As long as it's still in regard to Ridley (his resemblance to Red Eyes) and in possible colors for Ridley should he be playable (a dark Red-eyes like look or a more noble color like Blue-eyes), it's fine.
I know you wanna keep things on topic, but sometimes it's like you just leap at anything even remotely disconnected from Ridley himself. Yes there's that ugly history of Ridley threads, but there's a difference between keeping things from going too far off course and being too restrictive. When you start objecting at anything that doesn't immediately say "RIDLEY", you risk stifling the very atmosphere of conversation, which means you become just as much of a hindrance to proper conversation as going off-topic. Let some things ride out a bit before you blow the whistle. Then when it is actually necessary,
guide the thread back to where it should be. Don't just flash a big red
STOP sign and leave it at that. Maybe use the current subject at hand to start up something more closely related to the thread.
Let's say...
"That Red-Eyes Metal Dragon looks more like Omega Ridley. What do you think the chances are that Sakurai actually recalls his existence in Smash? Maybe not as playable or an alt-costume, but heck, maybe an assist trophy?" Just an example of creative moderating.
In all seriousness, I'm not trying to discredit your experience as a moderator or be obstinate to your enforcement of the rules. But I think you ought to give us
some credit. I think most of us are aware of the rule to stay on or as close to the primary thread topic as possible. But conversation ought to be allowed to flow at least a bit naturally. Usually things will steer back on course.
On the other side of things, that previous string of conversation that really did go WAAY off course (with some people being rather provocative much to my personal disdain), that was totally the right call to put the big mod foot down and call for a cease and desist. So clearly it's not wise to let your guard completely down. Unfortunately...