Baldur's Gate 3 is a massive game, which makes for a wonderful experience filled with unexpected story beats. Unfortunately, this also means there are some bugs that are still kicking about, even after several patches.
A lot of them have been squashed, and Larian's blistering pace has given us a whole new epilogue among other quality of life improvements: but some traces remain. One such bug is a hilarious interaction with Freecast, one of the illithid abilities obtained from chowing down on some brain worms. Minor Act 3 spoilers to follow.
Freecast is a toggleable passive that causes your next action to be (you guessed it) cast for free. No action cost, no bonus action cost, no spell slot expenditure, nada. It's a powerful gift from your wormy roommate.
It's also been bugged for several patches now. According to the tooltip, Freecast refreshes on a Long Rest. However, there are a lot of weird ways to refresh it. As someone who abstained from the power of the worm during my first playthrough, I had no idea—but a recent example on the game's subreddit tipped me off.
Here's how to use infinite Spell slots of any Level from r/BaldursGate3
Ant_of_Doom uses the Idol of Silvanus you can nick from the druid grove in Act 1. This item grants an aura that provides proficiency in the Animal Handling and Nature skills. Inexplicably, it also refreshes Freecast if it's been used.
However, swiping the idol has some severe story consequences. After doing some digging, I also discovered that there's another known way to trigger this exploit: taking off your underpants. Turns out, equipping or unequipping any item on your character will refresh Freecast. Here's some video evidence of it working on the current patch with my paladin boy:
The only caveat? Freecast is a partial-illithid power. You can only get it if you turn your painstakingly-crafted character into a failed goth with too much eyeshadow and rotten teeth. It also takes an action to equip or unequip an item like this in combat: so you won't be able to refresh Freecast in the middle of battle.
Still, this is an incredibly powerful way to apply buff spells like Aid, Heroes' Feast, and Death Ward scott-free. Gale's perusal of the Netherese Orb was all for naught—it turns out that the true secret to arcane power is to scarf down some worms, then take off your underpants (or a ring, if you're boring).