Ice pops are low in calories but ice pops are also pretty high in sugar content and sugar can cause weight gain over the long term.
However it's very unlikely that you're gonna gain much if any weight by just eating ice pops.
Ice pops are a nice low calorie treat when it's summertime out.
Ice cream on the other hand makes you gain weight more than ice pops do so if you like a nice cool treat and want to eat more of those cool treats then the ice pops would be better for you to eat than ice cream.
Eating a lot of ice cream can cause you to gain weight pretty fast if you eat enough of the ice cream.
But ice pops are less likely to cause much if any weight gain.