Dissolving folks quickly is hard work
Most acids aren't going to eat through you (or your average door) quickly -- while they denature proteins and dissolve metals, they don't have the oxidizing power to dissolve someone movie-style, and won't eat a doorknob faster than a drill bit. Even strong oxidizing acids can be sluggish by themselves under normal conditions.
There are some oxidizing reagents, however, that are capable of reacting that vigorously, and aren't completely out of reach of a supervillain. Mostly, they're used to deal with nasty cleaning/etching jobs IRL, far beyond the reach of anything you can get at the hardware store. Note that green and gooey aren't going to show up here -- gooey doesn't help you much when trying to get a vigorous reaction going, and very few things can produce a green color without getting eaten up by the stuff doing the dissolving. Bubbly, however, certainly will.
The term "piranha solution", or just "piranha" for short, has a very specific meaning to chemists -- it's a reagent produced by mixing laboratory sulfuric acid with 30% hydrogen peroxide. The partial in situ sulfuric acid peroxidation that happens combines with the ability of sulfuric acid itself to abstract water away from molecules and the ability of hydrogen peroxide to attack carbon-carbon structures by producing carbonyls, yielding rapid dissolution of whatever organic matter gets thrown its way. It is much less effective against metals though -- only about as effective as sulfuric acid by itself.
The other famed dissolving acid of history is aqua regia, a mixture of concentrated nitric and hydrochloric acids. While less effective against organic matter (nitric acid will oxidize it, albeit with a bit of sluggishness due to stuff getting nitro groups tacked on first), it is wickedly effective against many metals, even normally corrosion-resistant ones, due to the ability to form stable chloride complexes that drive the oxidation of the metal far to the right. It's also the most colorful of the reagents mentioned here due to the nitrogen dioxide, nitrosyl chloride, and chlorine that forms when it decomposes.
Perchloric acid is special, even as far as acids go -- it can attack and dissolve most metals all by its lonesome and is far more acidic than any other commonly produced industrial acid (its acidity puts it in the "superacid" category -- no other large-industrial-scale acid can claim that). Its technical grade is relatively sedate, but when concentrated well beyond that and heated, it is one of the most violent single-component oxidizing acids known, reacting violently or even explosively with organic matter. Atop that, many perchlorate salts are powerful oxidizers and even explosives -- ammonium perchlorate is used industrially in pyrotechnics and solid propellants, and friskier perchlorates such as heavy metal salts and alkyl compounds are well known to blow up at the first cross look they receive.
The one thing in our rogue's gallery that isn't acidic (I left elemental fluorine off as it's a cryogenic liquefied gas for most transport) is actually perhaps the most brutal of them all: chlorine trifluoride. This is one of the few reagents that will completely consume someone, pretty much irrespective of what they're wearing, in a matter of seconds to minutes. It will also do things like burn its way viciously through things that have already had as many oxygens stuffed onto them as they will ever take, such as concrete, as is fitting for a strong fluorinating agent. It is a volatile liquid stored under its own vapor pressure though, but does come the closest to meeting your color criteria.