The Hideous Blob was a small greenish-brown mound with tentacle-like protrusions for legs and a single, striped eyeball atop a short stalk. It was able to open a hole in itself, which was presumably its mouth. According to Spiff, the Blob was "monumentally" stupid, explaining how it simply stared straight ahead of itself, unaware of its surroundings. The alien was resilient enough to hold up against Spiff's Blaster on the "Liquefy" setting, a perplexing degree of toughness given its appearance.
The creature does not appear hostile, but it did defend itself by calling down an apparent alien authority upon being shot.
- The Hideous Blob is a Spaceman Spiff version of Susie Derkins.