Lama Achievement in Vampire Survivors

Note: This achievement does NOT require you to purchase the Curse stat upgrade (although it's not really an upgrade) from the Powerups menu between runs. You don't need to waste money on it, and you don't need to permanently curse yourself.

Aside from the Curse stat upgrade mentioned above, which is a completely viable way to get this achievement, there are a few other ways to unlock it:
 

1. Play with a character who starts with at least 10% curse. When you are choosing your character, check the stats for each on the left side and look to see if any characters has a curse that they start with. Numerous characters do. Simply reaching the 20 minute mark with one of them will unlock this achievement.
2. Unlock Torrona's Box (see Torrona's Box (10G)) and then select it during a run when you level up.
3. Pick up a Skull O' Maniac powerup from the ground on a stage. There is one northwest of where you start on Stage 1. Having the Milky Way Map will make this much easier to spot.

For the second and third options, you do not need to get the curse and then survive for 20 minutes after getting it. You just need to hit the 20 minute mark with the curse. This means you can wait until 19:59 on the clock and then pick up the item, if you want.