Crystal Attack
I wanted to add an attack to some enemies that fires a projectile that turns into a wall/obstacle after hitting. I implemented that in a couple ways actually but the main area where I used that is for several crystal elemental monsters. It seemed to make sense thematically, crystals can grow in real life, so let’s make that process a million times quicker and turn it into a projectile.
It works like this: when you approach one of these crystal monsters, it will instantiate one or more crystal bases and start rapidly growing crystals in your direction. Crystals will deal a bit of damage if they hit the player and they can’t be destroyed until they finish growing. If they hit a wall, they stop and turn into obstacles which deal no damage, but block the path and take three hits to destroy. This is how it looks in action if you encounter a single crystal monster:

I don’t plan to place too may of these monsters close to each other, but they will follow you while firing crystal projectiles, so theoretically you might end up in a mess like this, surrounded by 4 different crystal monsters:

I made the crystals grow slow enough so that they are fairly easy to dodge, but you could end up with a bunch of them blocking you, if you don’t destroy some of them as you go along. Here are a couple screenshots of me testing how it works:

