Biggest level difference you've found while invading

I have made thousands of invasions.

A very large portion of them have been with my level 49 Darkwraith at Anor, (+5 Chaos Iaito, maybe you've met me? ).

When I suspect I have invaded someone miles above me as far as levels I usually send out a friendly query as to their level. You can get a pretty good idea about how honest they are being by how the fight went and how their reply is worded.

Well, I just invaded a guy, and pounded the crap out of him, but I lost anyway, due to his insane health and him flasking about 6 or 7 times (which does not bother me at Anor, as opposed to the Kiln). I hit him with Lloyd's, knock his health way down, it wore off he found the chance to heal, ....rinse and repeat....

I sent him a message saying fun fight, (we had the knights involved at one point, he was casting pyros, miracles, magics, it was nuts), and asked him what level he was.

"I am level 644, lol, still learning pvp. "

I know there is no cap, but wow, lol.

....must be an old dragon head glitch I assume, I can't imagine leveling that high.

I'm not sure about the level difference, but I once got 1.2 million souls as an SL12 in a forest invasion. At first, I was chipping away at the guy, but it was going nowhere, and he was poise flasking (i.e., flasking through my hits). He wore mask or the mother, havels, and havels shield (yeah, that kind of guy), while alternating between a dragonslayer spear and a moonlight greatsword. Needless to say, this guy had a crap ton of stats. I resorted to chain backstabbing to kill him. I'm not sure exactly how many back stabs it took, but it took quite a few. The funny thing was that another invader arrived right as I was killing this guy. Imagine how thrilled he was to get 1.2M souls for doing nothing!

sl 50 i invaded guy in new londo, he was sl 300, took me a while to kill him after i asked him his sl and he told me, i was like damn.

Sad story....

....just invaded the guy again and now he has 2 phantoms with him and they are waiting at the spawn point.

....level 644!

What a tool, lol.

my highest was a 176 by my lvl15