When you first begin Bugsnax, the initial few catches act as a tutorial for how the catching works, but when Wambus asks you to catch him a Bugsnax Bunger, it feels like the training wheels have come off. Thankfully knowing how to catch a Bunger in Bugsnax isn't particularly difficult, it just isn't especially obvious either.
Bungers are Aggressive Bugsnax, meaning they will chase and ram their targets, and they love ketchup. However, if you try and lure them into ramming a tree, bush, or even yourself, in all cases they will just bounce off and continue on their merry Bugsnax Bunger way. What you need is to make the unstoppable force meet the immovable object: two Bungers need to collide.
How to catch a Bunger in Bugsnax
There are two ways to do this, both very similar in their set up and each includes creating a ketchup trail. Stock up on ketchup from the plant near the cave, and attract one of the Bungers’ attention by firing off a ketchup splodge, before luring them across the river into the middle patch with more dollops of ketchup. At this point, you can either keep luring that first Bunger across the river again, so that it meets the second Bunger, or you can lure that second Bunger into the middle too – it doesn’t really matter.
Once the two Bungers are together, the easiest thing to do is to hit them both with ketchup, meaning they'll run into each other and each will be knocked out for 10 seconds. Alternatively, you can place some ketchup between them, and as they both run for it they'll collide, so will again be knocked out. During the 10 seconds they're unconscious you won't need a trap, just go up to them and scoop them up with a net.
If you return later, you might find more Bugsnax around, including Dr Sodee in the lake, which will squirt water at any ketchup you lay down to make this method impossible. To get around this, you’ll need to use the grapple tool on Dr Sodee, then use the trap while they stare at you indignantly.