Several slimes have an effect that scales with the upgrade or downgrade, often asymmetrically. For instance, healing slime heals 1 extra hp for every +10 or -3.

Not gonna claim it's easy... but it synergizes well with the Twooze Company slime.

There is also an orb that multiplies modifiers by -2/-3/-3, while also healing you when it does so by 0/1/2. That -20 turning into a +60 can be very potent.

Add in the fact slime effects are stronger impacted by negative bonuses, you can have fairly super charged slime nodes, where the slimed node is a weak hit into a very strong boost effect.

It's definitely a very niche relic, but not impossible to use. If you have the Healing Balm orb it can be a pretty strong synergy by making that first healing slime generated heal you for +6, Twooze Company flat out just doesn't really have a downside with Bad slime (unless you already have other upgrade effects where the bonus is fighting the negative)