This has been suggested before, here's a link to the thread:

http://forums.spiralknights.com/en/node/106583

"The Blob: A great big mass of slime with a single objective; to eat you. And your friends. And family. Hey, while it's at it, why not everything else on Cradle too?

Literally a huge shapeless blob of opaque white slime that keeps changing its blobby shape as it moves. Has a rare chance to spawn in the place of any Lichen-type monster (including when lichens merge). Really big. Lotsa health, some knockback resist, heavy damage, slow movement speed. fast attack speed. Leaves behind a trail of goo when it moves, that causes Slow or whatever the thing the snow in the Grinchlin Assault mission did. Low chance to drop Celestial Ore for everyone on death.

3 types of attacks: They slowly stalk you and try to engulf you, a rare attack where they grow tentacles and try snare you and draw you in and engulf you, and a life-steal attack for after they engulf you.

They move really slowly, so in theory it would be sorta hard for it to catch up to you and attack. But if they are in range, they can almost instantly 'jump' and completely engulf you inside them, leaving you virtually no time to react. Fighting one with a sword is a rather risky decision, because of this. The tentacle attack has tentacles attack you, flailing around quickly and wildly. If you get hit without your shield up, you take no damage but you get snared, and begin to get drawn back to the Blob where it will engulf you. You cannot damage the tentacle if you're snared, but your teammates can. If they destroy it, you will be free. A bit like the Apocrea Harvester thing.

Once you are engulfed, you are pretty much dead. You cannot shield bump them off, you cannot attack, you cannot use sprite skills, you cannot dash or shield bash, ect. All you can do is try to slowly run out from inside them, like you were stunned. And they will move around to try and keep you from doing this. During this process, they constantly deal light damage to you, regening their own health a lot while they do this. Each (rapid) healing tick regens 100 health, and drains half a pip of your own health. In a way, a bit like the Harvester's soul steal attack. While life-stealing, they ignore any teammates you have.

This ends when
1) you die and the Blob continues on to your teammates
2) The Blob regens full health and 'spits' you out.
3) Your teammates cause enough knockback to the Blob so that it gets pushed off you (nitro and stuff would be very useful here)
4) The Blob is killed.
Unless you're playing solo, in which case it will spit you out when it has drained maybe half of your health."

Your suggestion and his seems very similar.