Heed my warning: You can only use 1 Piercing Tool for the Wicked Smile combo
A lot of folks surely saw the potential combo of Wicked Smile (shocks all relics on return) -> Piercing Tool (remove overcharge from all relics on shock) -> Wicked Smile again. I got 3 (actually 4, but didn't take one) Wicked Smiles on my run today. And I had the Piercing Tool, as well as a spare Surprise Disk (copies a relic's curse). So The Plan was to go Wicked Smile -> Piercing Tool -> Wicked Smile -> Piercing Tool -> Wicked Smile for some sick quality.
Spoiler: It didn't work. Unfortunately the trigger priority does not work the way I envisioned it - despite the positioning of my relics being "correct". I assumed the first Piercing Tool removing all overcharge will prevent the copied Surprise Disk from triggering (as when priority reaches it, it is not overcharged). Apparently, the trigger is saved, and the curse action buffered/queued. It still occurs right after, when no relics are overcharged.
Yeah, so if you were thinking about doing that - don't.
Video evidence of my greed attached.
Sidenote: Maybe you can actually string more Wicked Smiles after all? If the shock trigger is saved and action buffered, a Flickering Light right after should trigger despite already not being overcharged at that point, right? So Wicked Smile -> Piercing Tool -> Flickering Light (aimed at the Tool) -> Another Wicked Smile -> the same Piercing Tool again -> Wicked Smile #3 should be doable, right? 4th Wicked Smile is probably not doable though, I think... Or will the Thunder Amulet work for reviving the Piercing Tool?