I had a similar problem last year, at my year 2 of ownership. Just rotten egg smell, not smoking or dripping of liquid but battery did get hot. In my case I neglected to check the battery water often enough, it can dissipate and when low cause these type problems. Looking at top of battery you can see 2 caps that can be pryed off, use only distilled water and fill just until you can't see a space at the bottom of the tube. In my case, the battery was nearly completely dry, and ruined as it sounds like yours is. $100 lesson in my case. Google how to check the battery water.

Please be sure to disconnect from shore power and let the battery cool before you handle it, eye protection and gloves are a good idea also. If the water isn't low you may  have a charger issue. An auto parts store or your rv dealer will likely take the battery when you purchase a new one.

If you are within a year of purchase it may be a warranty item.

+1

That is a boiling battery. Disconnect and let it cool, then check the electrolyte level. It is likely low. The battery is probably bad now and will need to be replaced. The fluid dripping is sulfuric acid so you need not just gloves, but acid resistant ones like heavy duty nitrile gloves. Face protection is also advisable as is a way to keep the acid from contacting your skin or clothing. You may have a cracked case which would be the source of the dripping liquid.

My experience with boiling batteries was in an M577A2 (Command Tracked vehicle) on the Autobahn in Germany. The voltage regulator went bad and was boiling the batteries. In this situation, it was not the batteries at fault. We had to pull off and get out as the fumes were too much to take. We spent the night in sub-freezing weather in a rest area until the mechanics could get the part needed and effect the repair to get us back on the road to our intended exercise location.

One spark and they could have exploded. Thankfully, that did not happen. I agree with letting the battery cool down. Keep clear of it until it does.