It's the puddle of puke you created by drinking years old gasoline. It tasted good for a second, then it came out on its own volition. You're sad now that you couldn't get to eat the nutrients from the gasoline. Did you know an average gallon of gasoline has over 31,000 calories, and on average, a gas canister can carry up to 10 gallons of gasoline. With this, you could've drunk 310,000 calories of gasoline (assuming all the gas was still in there). The average Dersite like you only needs 2,000 calories per day. So, thinking this further, you could last 155 days with one single chug.
Speaking to this, the last time you had food was about 150 days ago, so...
Anyways, aside from gasoline, you also tried to fiddle with this chair. It was in the way of the console earlier, so you pushed it over here. It also appears to have raised itself a lot in the journey up. Bugs probably. A cockroach can be crushed by a shoe but can survive several nuclear blasts. It's a shame none of the monsters were based on cockroaches, otherwise you'd have someone to talk to. Alas, the life of a soulless stray is bound to solitude and singularity.
But hey, there's still that cat you can talk to. Maybe also that birdguy, he looks like he could listen to your rants.