Proboscis
Proboscis is one of the original classic items with the text "When you do X, do Y". This has pretty much always been a recipe for success, to the point where many pre-existing items with similar text have long been nerfed or reworked.
Proboscis is no exception, though it eventually found its way back.
While it's not always the most available item, the potential of its power makes it well worth seeking out. The most common way you'll find it is by getting a lucky drop from the Giant Mosquito PvE Encounter.
It's incredibly easy for Vanessa to create an absurd amount of Slow triggers, and each one individually procs
Proboscis. This creates a Weapon that effectively cheats Cooldowns as it rapid fires non stop.
With enough Slow triggers in place, all that matters is finding a way to reliably scale its Damage. Solve this equation and you'll have assembled a monster. However, during the early game feel free to take advantage of flat Damage skills for a more immediate boost.
Kripp had a Restorative enchanted
Proboscis which gave the build a ridiculous amount of sustain. Aside from one-shots, this pretty much ensured safety throughout the entire fight.
Kusarigama
Kusarigama is absolutely ridiculous alongside
Proboscis. It's essentially like a build-your-own
Mantis Shrimp, except it grants all the upside with no cost. The fact it can scale other Weapons allows you to get around longer Cooldowns (ie
Mantis Shrimp) while still benefiting from the scaling.
It provides scaling to up to two Weapons, creates Slow triggers, and can become an additional threat of its own. This item does everything. In all fairness, there's a pretty good chance we'll see nerfs at some point, because
Kusarigama is nuts.
Slow Package
Shot Glasses has become the pinnacle item for spamming Slow triggers. The more items you have, the more Slow triggers it creates, quickly leading to absurd scaling. However, it does require Ammo, so make sure you either have Reload, or can expand its capacity via upgrades and/or
Gunpowder.
Clamera is another Slow staple thanks to its immediate on-start effect, and
Tripwire allows your opponents to scale your items for you. It's also worth noting that
Tripwire has some incredible enchantments, so be sure to take full advantage whenever it's available.
Orange Julian
Orange Julian allows
Proboscis to reach much greater Damage levels than normal, but with a much slower startup. It's important to have direct Haste support to ensure
Orange Julian goes off faster. Once activated, your DPS skyrockets to astronomical levels.
Keep in mind that it's only worth pursuing
Orange Julian when acquired early enough during the run. It takes time to scale its Damage, and when
Orange Julian is available, it encourages taking more of an Economy route (which you may not have setup prior). Otherwise opt for additional Slow/utility items.