Specters

[fingersome]

As soon as you gain any amount of warp there's a small chance to spawn a new mob - a specter. Specters would look like shadows of existing mobs. Initially, they wouldn't harm you, but they spawn regardless of light level and make a strange echoey version of the existing mob noise.

Specters health would be proportional to your warp level. with low warp, a single punch would disperse them into a cloud of shadow. As you gain more warp they become more tangible and harder to destroy. As you gain more warp the spawn frequency would also increase and with a moderate amount of warp they would be able to attack you.

They would drop umbra essentia crystals, and void seeds rarely.

[devtn2001]

It's like monsters from don't starve.

[AmyMialee]

You'd need some way to prevent them from showing up or deal with them more effectively. I'd need to be something unique and not be affected by normal warp ward, instead of just a clone.