I will only put the strong monsters for debate. No point of putting cultsits, etc. No spawns/masks would be included, either. Also I'm aware the title says "strongest" but you should really choose the monster that has the largest impact.

Well the Dhole pretty much "blocked" all the contenders, which left us with these:

vs.

I guess it's pretty obvious Dhole has greater impact, although arguments can't be made for the Rat: It's stalker; it's pretty much impossible to evade; and if you only have good items you're pretty much screwed. Most of the time you have useless items, so I'll go with te Dhole.

Previous Great Debates

Aren't there any more intimidating circle monsters? Crawling one? Wizard Whateley?

Well, Dhole hands down. Rat-Thing can be annoying when cornered, but I usually have something to spare. Last game I happily gave up McGlen's Tommygun because someone else had found another dropped by a Tcho-Tcho.

Carwling One and Wizard Whateley are pretty much strickly weaker than Dhole. I guess it's a pretty bad debate so I'll move on to the next symbol.

Dhole definantly. Rat Things have too many variables to be dangerous, like only have good items.

Dhole

"Below him the ground was festering with gigantic Dholes, and even as he looked, one reared up several hundred feet and leveled a bleached, viscous end at him." —H. P. Lovecraft and E. Hoffmann Price, "Through the Gates of the Silver Key".

The Dhole. A Rat-Thing on a gate won't prevent me from entering the location. The Dhole most certainly will.

Yeah, Dholes are so freakin' nasty. I bumped into one in an otherworld "A Monster Appears" at full health and sanity and with good items. A few unlucky rolls later, and I was fed to Yog. Even on the main board, they present a formidable road block when they appear, as nobody in my group (myself included) has the guts to face one.