A lot of people have had complaints about the threatlist. I have some concerns myself, but one thing I very much like about it is the fact that only the 110+ base Speed scarfers are listed as necessarily being able to revenge kill. This opens to door to speed-boosting abilities. In particular, I believe Unburden is by far our best chance of making Belly Drum work in OU. Unburden, with a Sitrus Berry and even HP, means that using Belly Drum will essentially double CAP 6's Speed in addition to its large Attack boost, and do so at the cost of only 25% HP (with the limitation that the CAP still has to have over 50% to use it). This only works once in a given battle, which makes it an all-your-eggs-in-one-basket strategy, but Belly Drum itself already has strong shades of that with the large HP loss making it highly impractical to use more than once. Unburden makes it much more reasonable for that one shot to actually lead to a sweep by preventing revenge killing by unboosted Pokémon and the slower scarfers. This does admittedly constrain our Speed stat to be 70 or below and quite likely close to that exact number in order to underspeed the base 110 scarfers without doing the same to every other scarfer in the tier. This is unfortunate, but if doing that is a goal (which I think it must be: losing to every scarfer makes us bad, simple as that) then any ability will lead to an equally precise number. Of course, if doing that is not a goal than even Unburden doesn't require such precision. There have already been suggestions that Unburden is too good. However, I think these concerns are overblown. ginganinja posted some calculations that suggest the healing from Sitrus Berry makes you "unrevengeable". To some extent this is a red herring because you have the option of running Sitrus Berry with any ability (except Gluttony, which presumably wants Salac Berry). Even if it is accepted that problems caused by Sitrus Berry are inherent to Unburden, those calculations are based around the assumption that "your HP stands at exactly 75%", which is the case only if Stealth Rock is not on the field and you were able to set up without taking a hit. This is not the typical state of affairs! It's not unusual for a resisted attack from an offensive Pokémon to be doing 25%, and quite typical for it to be doing the 12.5% that nullifies the Sitrus healing in combination with Stealth Rock. (Even Scizor's U-turn, which we doubly resist, does more than 18% minimum to the 80/80/80 bulk ginganinja is assuming.) In fact, with Sitrus Berry, your typical HP after a Drum is probably around 50%. Unburden is a very powerful ability, and that can be scary. But I really don't think there is anything to be afraid of here. Unburden doesn't make it any easier to set up, and while it makes revenge killing more difficult, we are firmly in control of how difficult it is through the stats stage.