You can buy candles designed to drip artfully. The ones I've seen and bought were marketed for Halloween and to lovers of spooky decor. Red on the inside, and black or white outside, they are supposed to give the impression of blood streaming down the candle as it melts. I tried a few.
I'm not sure if this type of candle predates or was inspired by the 1992 film Bram Stoker's Dracula, but the opening transformation scene - where blood pours from the cross, cherubs' eyes and candles - is invoked by some of their branding. I've had a packet of Weeping Rose taper candles in a drawer for years, waiting for the right occasion to use them. I recently acquired a three-wick pillar candle from the same range, and more tapers unsubtly packaged as Vampire Candles promising to 'BLEED' red wax. Finally, I had a pair of Dreadful Drip taper candles, which I've mentioned in my Halloween Candles (Yankee Candle) article.
The results of lighting the candles are pictured below. I've used the tapers before, so I was prepared for the mess they generate and put them in old wine bottles, rather than using nice candlesticks. Wine bottles are a good choice for regular candles too, if you don't have any candlesticks at home, especially if they have pretty labels. My bottles didn't have a fancy label but I appreciated the name: Ghost Vines, printed in silver on black. Used multiple times with regular candles, the bottles can get coated with small wax drippings and look quite good. With dripping candles the coverage of the bottle is much chunkier and less even.
The Vampire taper in my experiment lasted for around 3.5 hours, the other two a bit longer. There was lots of dripping, but the red colour mixed with the outer black or white, causing it to look less blood-like. It quickly ended up a dark maroon with the black candles.
This was the first time I've tried burning a dripping pillar candle, and probably the last. It burned for a few hours before extinguishing, and during that time it made a huge amount of mess! If you try lighting one of these, expect that the wax will flow all over the place, unless contained by a large plate or bowl. It looked impressively lava-like as it spilled out of the candle, but it would likely stain fabric and carpets.
Overall, I think these candles don't really achieve the blood-dripping effect successfully. The one that came the closest was Yankee Candle's Dreadful Drip tapers, because the white outer didn't overpower the red colour entirely. There's also a lot of cleaning up to be done after burning these candles, so personally I'll stick to regular candles on the rare occasions I use them.