Problem with iPhone!!

Its a very good App and dont give me wrong I love it but I dont know if this happens to other phones but on iPhones it like makes my iPhone glitch out and turn off and like it says it has no more battery but it still has like 60% or 70% and then like five minutes later it turned back on and it still says 60 or 70% but then I go back into the Snapchat app and it goes from 70% to 1% out of nowhere!!

Bland kasha about Snapchat, v10.4.1.0