Goblin Sorcerer

Sorcerers come with a goblin invasion and nothing else brings one. They are a small slice of the crowd, so most of a wave is melee with a handful of these mixed in, and the handful is what damages you through your own walls.

It blinks in, waits a moment, then throws a set of three shadow projectiles one after another with a visible wind up before each. Then it pauses and blinks again. The projectiles pass through solid blocks, which is what separates it from the Goblin Archer: terrain does not protect you, and a sealed box only means you cannot see what is shooting at you.

Hitting it stops everything. A hit resets the teleport timer and it cannot throw anything until after the next blink, so a fast weapon with reach keeps one permanently mute. Aim high, because the projectiles leave from its head rather than its body. The projectiles themselves are fragile and any weapon or shot that touches one destroys it, which is worth remembering when a volley is already in the air.

The teleport is not free placement. It needs a solid block to stand on with clear headroom above, no lava directly over the spot, and it has to land inside a square centered on you while staying a short distance away, so it will never drop onto your head. The check reads where you are heading rather than where you are, so running does not throw off its aim. Platforms and planter boxes do not register as solid roofs, which means it can appear inside a platform floor. If it finds nowhere legal it stays put and restarts the cycle, so an arena with a genuinely sealed ceiling over every walkable tile pins it in one place.