I made wort for my 5 gal brew by dissolving 32 oz of confectioners sugar and 55 oz of dry malt extract. What effects of large amount of sugar can I expect?
By my rough calculations it's about 1kg in 18 liters - to convert to units I can use my intuition with. This means you provided a bit over 5 Blg worth of fermentables by adding sugar. Not bad. I did more, on purpose.
First thing, you just increased your ABV by about 2~3%. That's neither good or bad.
Second, you didn't provide anything that usually goes with malt. No nutrients for your yeast. No dextrin for sweetness. No compounds to form malty sweetness. In some Belgian styles that's exactly what you want - Belgian yeast can use this all right, and having increased alcoholic content with high drinkability is their aim. But it only stands true for strong beers, usually way over 15 Blg and 7% ABV.
If I understood your comment correctly, you had 55 oz (about 1.5 kg) of dry malt extract. It means sugar makes up 37% of your solids. That's a lot. Way too much for my taste and your beer may taste watery or express cider-like or moonshine-like tastes. And all you probably got was 12 to 14 Blg - 5, maybe 6% ABV in finished product. So it's not too good.
Depending on malt extract. I would expect something in the range between "water with alcohol" and "a bit watery/cidery" result. If you're lucky, and it'll be the later, you may still get a beer that will be pretty drinkable, just don't expect anything award-winning. And be careful with hops - you lack malty sweetness to counter and balance their bitterness.