Tiger the dog and Fluffy the cat were the center of chaos at the wedding of Carol and Mike Brady’s marriage in pilot episode. Fluffy was never seen again but Fluffy was seen in a few episodes. In season two Tiger was hit by a vehicle and killed on the Paramount film set. Some say it was an automobile, others say it was flower or pizza delivery truck.
The trainer never told the studio or the show’s creator Sherwood Schwartz. Not knowing what to do the trainer found a look-a-like from the pound that was untrained. They still had scenes to record for the episode. Of course with the dog being untrained the dog kept running off set. To complete the scene they had to nail to dog’s collar to the set to keep the dog in position. “Tiger” was never used again but you kept seeing his dog house even to the end of the series. The reason was that during production early on in the series a studio light fell on the Brady’s artificial turf backyard and burned a hole in it. The dog house was placed over it to hide the burn mark!
Here is an interview with Brady Bunch Creator Sherwood Schwartz on the incident: