The thought is nice. I wouldn't want a rubber bug. A nice thank you, along with remembering the discovery on my performance evaluation, along with a bonus would suffice. It's our jobs to find bugs. If my manager did something like this, I'd take it as the condescending insult it is and walk.
Toys are for kids.
Such is the process in business. This was a visual, fun, thank you for a job well done, right now. You can use your own criteria for a 'job well done'. Right now it was a critical bug. Next time it may be hitting our deadline, a product launch, etc.