Manipulative Senior at work, what to do?

Hi all, so I’ve been on this project for a couple months and it took me a while to realise that my senior doesn’t do any work but gets work done by me. They say they’ll do things, it remains undone for weeks, sometimes months and then they very slyly pass that task to me.

To give an example, in the recent times, I noticed how when me, my senior and their senior are on a joint call, at the end of it, my senior say they want to discuss how to divide those tasks to find h them and when their senior leaves the call, they ask me to do it all and that they’ll review and send it to the senior.

This is just one of many instances and it’s really annoying how one can away with this at work!

Has anyone come across such people at work? How do you handle this?