there seems to be a lot of misconceptions thus far about magnemite's team. 1) magnemite is not always leading with golem and it's ridiculous to think that, i don't know why people feel like leading with a stealth rocker is the only way to go about leading. 2) magnemite is just going to mindlessly let his golem die to barbaracle so that it can't check scyther. while there are possibly ways to win for dundies, magnemite has a massive advantage.
in his position i would probably lead with either sneasel (which is the most threatening pokemon to dundies's team) or roselia (since it takes advantage of barbaracle if dundies chooses to lead with barbaracle because he likely wouldn't lead with bouffalant off the bat due to magnemite having a) a perfect counter and b) bouffalant being able to switch into roselia well enough. barbaracle is a likely lead for dundies, but golem isn't a likely lead for magnemite. assuming barbaracle vs sneasel dundies is likely to not attack off the bat because then sr doesn't go up so he can't break golem's sturdy, and even though sr isn't that much of a problem against magnemite's team he is likely to have 2-4 life orb users so it aids immensely in them being worn down. therefore, in barbaracle vs sneasel, dundies gets sr and magnemite gets a kill assuming likely prediction scenarios OR dundies goes to avalugg but then that loses its item which aids magnemite a lot. sneasel should be going knock off + low kick, not low kick first. assuming roselia lead a 50/50 occurs between taunt/toxic spikes and sr/giga drain BUT it is more likely that dundies sacs it for sr or goes to bouffalant on a predicted giga/sleep powder. to be honest i would taunt because it is imperative that toxic spikes don't go up on a bouffalant switch because then avalugg basically has no chance of walling what it needs to and magnemite auto-wins. this gives a free giga although this is just what i'd do; it IS a 50/50.
also both scyther and raichu have 0 switch in opportunities so in order for them to actually do anything they have to sac something which is a gain for magnemite anyway. when scyther comes in there's no way it isn't u-turning on the golem because he can't afford for magnemite to get a free sr so magnemite can take advantage of that by going to haunter which does a lot against dundies's team (bear in mind that in the actual battle none of this will happen because everyone has read this thought process but i'm reading this assuming a random ladder matchup where no one knows anything about any of the other sets). if magnemite assumes scyther is sd then he should go to golem but the team style implies a cb scyther (well, it did to me simply because of the placement of bouffalant but it's kinda bad to make assumptions o.o). if it was a sd scyther obviously haunter is a bad switch-in because it's knock offing the first time but cb scyther can't spam any move other than uturn because it's too imperative for sr not to get up or he straight up loses to mightyena + sneasel. scarf raichu can attempt to revenge one of them but it loses to double priority from any two members. also the weakness policy on golem is important to remember because it can potentially break things after scyther has come in on sr once and sr is still up so golem has no more job seeing as everything else kills scyther with priority at that point. toxic spikes are a huge advantage this game but they aren't mandatory; in fact sludge bombing the bouffalant switch in is better if avalugg is already dead/heavily weakened.
overall i can't see any way of winning with dundies's team that can't be played around; its reliance on choice users, and slow sweepers is easily taken advantage of by magnemite's heavy offense. when we look at all of dundies's pokemon, none of them find it easy to win. misdreavus is ohkoed by lo adamant sucker, sneasel knock off, can't break roselia who just sleeps it, is ohkoed after rocks by haunter, basculin does a shitton and missy can't ko obviously. scarf raichu isn't doing anything barring multiple parahaxes due to golem/roselia/shitton of priority. avalugg gets worn down easily and is by no means a win condition in any sense of the word. golem forces a shitton of dmg after avalanche, roselia sleeps and does a lot, sneasel removes item, haunter beats it, mightyena beats it after not much prior and 1 moxie boost. scyther is moderately annoying but sr + any of the teams 4 priority members make it for easier to handle in practice. bouffalant can't touch haunter. barbaracle is killing itself just to get rocks up.
meanwhile look at magnemite's team. sneasel does a shitton to everything. mightyena cleans with minimal damage, roselia gets free tspikes often, subdisable haunter shits on the team, basculin admittedly has a switch-in in avalugg but hey you're baiting it in to get tspikes + sr on it! also i would always double to something that beats avalugg with basculin out here since you get it to take sr + tspikes + psn dmg 6% + force it out which is kinda great lol. OR 12% actually if 1 layer. yes 12%. golem gets up sr on locked raichu, locked scyther, avalugg avalanche who then takes a shitton from stone edge… dundies unfortunately can't win this matchup barring magnemite choking multiple times.
fun project.
edit: since people are telling me it's too hard to read in one block of text..