The original X-Men vs. the Silver Age Legion of Super-Heroes?

That’s why you kill the boyfriend first. I believe that strategy worked out famously for the gentleman who implemented it.

He was both more and less powerful than Rogue. More in that he didn’t have to have skin contact; less in that he didn’t deprive the other person of their abilities and in that the person he was mimicking had to stay fairly close for him to keep it up. Any Kryptonian-type could beat him easily; just fly a mile up and knock him out with some variant of super-breath.

The man speaks the truth.

Should start a thread about which one the early female team-members of the Marvel Universe was the most useless:
-Invisible Girl
-The Wasp
-Strange Girl

Skald’s already covered the guy’s 60s-era limitations, but for the sake of completeness:

Yes all around; he copied Iceman’s powers before he even realized the youths in question were the X-Men (that’s how he figured it out), later used Jean’s powers by idly wishing he could reach a nearby salt shaker that promptly floated into his hand, and when battling the X-Men in full costume imitated the Prof’s telepathy to relay the usual warnings and tactical advice (except, of course, he was intentionally steering 'em wrong).

In the given situation, Vi and MEL’s standard combat techniques are useless (you can’t destroy your opponent’s weapons when they’re fighting unarmed), and assuming they’re sticking to the standard ‘no-kill’ policy, and the implicit ‘no crippling injuries, either’, Tenz’s powers can’t come into play at all, and Vi’s most effective combat-related abilities are out.

But, let’s look at Vi and TL in combat - they’re both masters of 'now you see ‘em, now you don’t’ - Constant multiplying and demultiplying, or shrinking and growing as they go on the attack or on defence (the former being an integral part of the Carggite martial art Tri-Jitsu, in the post-Zero Hour continuity, but a perfectly valid strategy for all incarnations…Imskians have never bothered creating a martial art based on their racial ability) - it’s not enough to make them combat monsters, without training (which they do have - starting in the late 60s, Karate Kid trained the entire team in martial arts, and even before him, they had combat training - just not taught by the galaxy’s greatest martial artist), but perfectly effective combat powers.

But, to demonstrate the usefulness of Tenz and Vi’s powers, let’s change up the situation a little - it’s the Legion against the whole of the X-Men roster.

The two of them would be absolute terrors vs Forge, Cable, Omega Sentinel, Danger, or Box, and Tenz would be Gambit’s worst nightmare. Since all of the above use weapons, they can be disarmed - Vi’s standard strategy is to shrink into mechanical or electronic devices and disable them from the inside - so Forge, OS, and Danger’s mechanical parts (actually, all of Danger) are vulnerable to her, as are Forge and Cable’s weapons, and Box’s armour. I’m not sure if Cable’s technorganic limbs are vulnerable to that - probably not.

As to Tenz - his powers are to eat and digest almost everything - regardless of hardness, toxicity (to non-Bismollians), energy released (he’s eaten bombs and radio-active materials with no ill effects beyond slight indigestion), or even whether he can reasonably fit it in his mouth (he once hollowed out a meteor for him and a couple other Legionnaires to use for transport). There are two exceptions to this - he’s never demonstrated the ability to eat Intertron (though I don’t think it was specifically stated that he can’t, it kind of ruins the point of Inertron if he can - I assume adamantium is of a similar nature, which is why Wolverine is not on the list of X-Men he could beat), and he has exactly once been adversely affected by the energy released by something he ate - when he ate the Miracle Machine, a device from another universe which can do literally ANYTHING, so the energy was rather unique. So, anything Vi could disable, he could eat, plus Gambit’s staff and cards. Juggernaut I considered adding to that list, but I’m not sure how the mystical qualities of the Bands of Cyttorak would effect him, or if he’d even try, given the chances of accidentally biting off too much and eating part of Juggy’s arm.

I’m sure you didn’t intend to insult Ms. Van Dyne and will allow you the opportunity to apologize before.

At some point after Giant-Size X-Men #1 it was stated that Cyke’s optic blasts had come back more powerful after becoming un-depowered upon returning from that island. There was a bit about being able to level a mountain, or somesuch. I’m sure it has been well and truly forgotten in canon as the years and years of powerups and power-redefinitions and whatnot have gone on.

Cyclops was the most formidable of the original X-Men when they first started out… but that wasn’t saying much. He was competing against snowballs and levitating salt shakers, after all.

Hey, now! Jean was super-effective against Slug Man!

Since the LSH has Brainy on their team, and oodles of extra people of questionable use in the main battle, the obvious solution is to have Tenzil sneak in (with Espionage Squad help, probably), and eat Cerebro.

Even if Saturn Girl can stand up to Prof X, it’s doubtful she’d be able to do so if he’s backed by Cerebro.

Let us not ignore a founding member! Cosmic Boy can take out most X-Men weaponry as well as rendering Wolverine useless. Edge still goes to the Legion.

You’re not saying that BRAINY is of questionable use in the battle, I hope. I don’t think there has ever been an iteration of the Legion in which he was thought anything other than the most valuable member–even including the Big Three & a Half.

I love Cos, but he needs to sit this battle out. At least half the X-Men’s off time has got to be devoted to war-gaming against Magneto, who could do anything Cos can and far more effectively.

Whups. No, I meant that since they have Brainy on their team, he’s sure to think of things like having Cerebro eaten.

Or having Vi or PG go after Scott’s visor, for that matter. Get that thing off him and he’s as big a menace to his own team as he is to the enemy.

So throw in the 1963 Brotherhood of Evil Mutants on the X-Men’s side…

Magneto vs. Cosmic Boy? (as I mentioned earlier)
Toad vs. Bouncing Boy?

I’m not sure who Scarlet Witch’s and Quicksilver’s most interesting challenges would be with.

Why would they bother? Jan can turn it to Just have Kal, Kara, Mon, or Jo punch him out. The optic blast is only a danger to Jo.

For a more interesting match-up, I’d like to see the X-Men as I first knew them – that is, Cyclops, Wolverine, Storm, Banshee, Colossus, and Nightcrawler – against any six non-Kryptonian or Daxamite Legionnaires. Hell – any TWELVE such Legionnaires. Unless one of the Legionnaires happens to be Brainy, the X-Men win both times.

Back in the glory days of Claremont and Byrne, it was established that Danny Rand could wipe the floor with Wolverine and Nightcrawler and Banshee without even bothering to fire up the Iron Fist. So even if Karate Kid doesn’t have his flight ring, that’s half the X-Men down…

Colossus vs. Colossal Boy…

Any battle that includes adamantium-boned Wolverine (and possibly Colossus as well) and Cosmic Boy should, by any logic, have the latter casually immobilizing the former(s).

Hmm. I’ll concede that Silver-Age Val can defeat almost any non-Kryptonian who doesn’t have a ranged attack, and many ranged attackers. If he’s one of the Legion’s six, he’ll do the mutants a ton of damage.

But then he might not survive. I’m certain Val could kick the crap out of Colossus, but that’s going to result in Storm seeing her pseudo-little brother go down, his face dented all to hell, assuming that the opponent has super-strength, and frying him with a lightning bolt she’s been holding in reserve for the Juggernaut.

Things get ugly from that point.

Frying Val is not recommended. Just ask Nemesis Kid about that.

Kinda my point. Val is the character most likely to get misjudged in battle, and he’s going to get pulped or fried. That’ll result in any Legionnaire whose name isn’t Clark Kent saying “Fuck the no-killing rule.”