I need help with the plant under the agave. It is very heavy and was laying flat when I got it. It's in the same pot but I have propped it up with some rocks and by laying it on the pot above. Please tell me the following:

First of all, what is it?
Should I stake it?
Is it supposed to grow upright?
Should I cut it at the joint and plant the segment?
Lastly, what else should I do?

Thanks everyone!