Bubur Jagung is basically sweet corn swimming in santan and sugar. It is a warm dessert porridge, very common at pasar malam and kopitiam dessert stalls, and it looks totally harmless in the bowl. But 360 calories for a dessert portion is not nothing. To be upfront, the numbers here are a ballpark estimate because solid lab data for Malaysian hawker bubur jagung is thin. What we know for certain is that the fat comes almost entirely from the coconut milk (17g fat, mostly saturated) and the carbs come from corn, sago, and sugar stacked together. If you are someone trying to lose weight and you finish your nasi lemak and then bowl this down as an afterthought, that is an extra meal worth of calories you probably did not account for.
The version you get matters a lot. A stall using diluted or low-fat coconut milk drops the whole thing to around 220 calories. A generous pasar malam bowl with extra santan and gula Melaka can push past 450 calories. If the stall adds cubed sweet potato (ubi keledek), that is another 40 to 50 calories on top. The sago pearls themselves are pretty innocent at only 30 calories for 30g. Portion size is the other lever since most stalls just ladle freely, and a generous pour can easily be 320g to 340g instead of the standard 280g.