The Clumsy Robot will sometimes eat bologna sandwiches during the battle. The game tells you that this heals up all of its HP, but this is not true! The sandwiches have no effect at all. The battle ends after you have damaged the Clumsy Robot by 962 HP.

On most turns, the Clumsy Robot doesn't attack at all, but when it does, it sometimes uses a very damaging attack.

Bombs and Bottle Rockets don't seem to work on it.

It starts with a PSI Shield α, so use the Neutralizer to get rid of that shield, allowing you to use PSI attacks on it.

The Clumsy Robot is considered a metallic enemy, so you can use Rust Promoters to do 200 HP damage. You can buy some from the junk seller in a back alley of Fourside.

Focus on bashing it with physical attacks, or, if you have the Neutralizer with you, use it and then attack with Ness's PSI attacks.

Overall, there is no need to panic. As mentioned above, the bologna sandwiches don't actually help the Clumsy Robot at all, so don't worry.

Once the Clumsy Robot has been stopped, you can go into the room where Monotoli is waiting with Paula.