The acid monster was only from a hallucination brought on by the Scarecrow's fear gas.
Physical appearance[]
It was a large dark green monster with red eyes and drips acid, while also leaving a stench of it wherever it goes.
Personality[]
It was intimidating do to it's large appearance.
History[]
Scooby-Doo! Team-Up[]
It was a hallucination that Robin was seeing when he saw Velma freakout over the giant spider they saw earlier. (Which was what she saw because everyone was separately caught in the fear gas)
Appearances[]
- Scooby-Doo! Team-Up
- #2. Who's Scared? (Hallucination, no lines)