A "MOD APK" is a modified version of an original Android application. Typically, these are altered by third parties to:

: Since you must grant permissions (like storage or contacts) to install an APK, a malicious mod can scrape your entire phone’s data. Official & Safe Download Methods

Downloading files from unverified third-party sites like "Ocean of Games" (which primarily hosts pirated PC games) for a mobile educational app is dangerous for several reasons: