Can you describe what chew toys he has?

I am more inclined to say your rabbit just wanted to eat foam, as many rabbits tend to do because something about foam, plastic, cardboard, fabric… they all seem appetizing to some rabbits.

From my experience, if you are observing him eating and pooping as normal, the foam is probably already out of his system or is working its way through (depending on how long its been and how much). Rabbits get their mouths on things that are not good for them pretty often across the board, so as long as it wasn’t a concerning amount paired with poor health signs, they usually do a fine job passing it on their own because they chew things very thoroughly before swallowing. My best recommendation is make sure he’s continuing to eat hay and drink, as fiber and hydration are key to keeping a rabbit’s GI system running smoothly!

My Fable is classified as a “destructive rabbit”– within the first month of adopting her, several baseboards, wall corners, carpet spots, sofas, shirts, pants…. permanent damage. Alas. That being said, it took a bit, but we did eventually find what type of toys she likes redirecting that energy to, and more importantly, how to present the toys so they are enticing for her. She doesn’t like small toys that some rabbits may “toss”– she likes things that are anchored– so fastened to a wall or I’m holding them for her.

Fable’s main ways to expend her chew energy are plain cat scratchers (free or anchored to wall):

.. and fleece blankets tied at various heights to a wall of her pen, so it’s infinite digging and chewing.

If your rabbit has an inclination for cardboard stuff, I wouldn’t necessarily be afraid of offering them as toys. In all honesty, Fable eats a ton of cardboard but she also eats a ton of hay and drinks a lot of water, so ultimately she has never shown ill-signs from high cardboard consumption. Definitely observe if that’s not the case for your rabbit, but personally cardboard is the best toy for Fable and I’m not going to stop offering it because it’s cheap and saves my apartment from damage!

I agree with Wick. Rabbits can REALLY love cardboard. I had a bun that insisted on remodelling his cardboard houses in the middle of the night though, so that can be a problem if your bun is free roam and has houses in your bedroom. I had to take away the bedroom houses at bedtime  so he had to remodel (=improve) cardboard houses in the living room instead, which didnt wake me up.

The cat scratching boards of corrugated cardboard are great.

I also believe that the foam has come out the “natural way”. Rabbits chew stuff, they can’t swallow big chunks like dogs and some cats do. This is very good because it means that whatever is ingested can mix with whatever else is in the tummy and get expelled with the poop.

It is often so that rabbits love simple stuff like cardboard boxes and toilet paper rolls. It’s kind of disconcerting when you’ve spent money on fancy toys and the rabbit is only interested in the box they came in 🙄😂