EXTRA: Seal II Achievement in Vampire Survivors

As the description says, you need to use the Banish ability 20 times in a single run. Note that it doesn't need to be used strictly on weapons, as items (such as Armor, Hollow Heart, etc.) also count toward the 20 needed.

This is quite easy to do with Sigma since she starts with over 100 Banishes. You should probably level up your starting weapon a couple times or grab a couple more weapons first, just to be safe, but then just Banish something every time you level up. The only way to see how many Banishes you've used is to check how many you start with (for me, it's 118) and then subtract off 20. Once you use 20, you can just quit the run to unlock this achievement.