And what would you do?

It is impossible to imagine just what it is that suddenly unleashes a child's imagination. Ben has recently discovered the magic capabilities he has of imagining the absurd, the ridiculous, the incredible. It is the ''what would you do if . . . ?'' stage.

I think I can pinpoint the scene that led to the barrage of absurdity. It was while we were making corn bread one evening. Ben was putting in the baking powder and wondering what it was for. ''Baking powder makes the corn bread rise so it is light and fluffy,'' I said.

''Well, what would you do if it got so big it filled up this whole house?''

''I would probably call in all the cows and goats to eat it up.''

I realized my mistake. I gave his ludicrous question credibility by answering it. He liked my make-believe answer, and the questions continued through dinner and into the next week.

''What would you do if I ate my plate?''

''I would be very upset. These are my good plates.''

''Well, what would you do if I ate one of the old plates?''

''Oh,'' I stammered, ''I probably would say, 'Why don't you have a banana instead?' ''

''What would you do if an elephant came in our driveway and ate the tires off your car?''

''I'd stay home.''

''What would you do if the Incredible Hulk pushed over this house?''

''Oh, I'd probably jump up and make him put it right back.''

''But what if he wouldn't?''

''I'd spank him a good one.''

His eyes bullwinkled. ''The Incredible Hulk? ''

''Sure. What would you do?'' I asked.

''I'd hide.''

''Maybe that's what I'd do, too,'' I reconsidered. ''You do realize, I hope, that you are asking really silly questions. Nobody pushes over houses, or eats plates, and elephants don't eat tires. It's fun to think silly sometimes, but not all the time.''

''I know, Mom, it's a game.''

''I think I'm tired of it,'' I said candidly.

He was standing on a chair at the kitchen sink, washing off the afternoon fun. ''Can I just ask one more thing?''

''One more.''

''What would you do if this water turned to mud?''

''Now how would it ever do that?''

''I don't know. But what if it did?''

''I guess I would be shocked.''

''I guess I would always be dirty!''

''I guess so.''

Our truce did not last long. Curiosity got the better of him and without realizing it he engrossed me in another crazy conversation. Finally, he asked me a question I had no answer for. I fought back.

''Ben, what would you do if I stopped answering these nutty questions?''

''Oh, I'd probably have to ask somebody else who knows.''

''What a great idea!''

It did not take him long to find another authority on make-believe. ''Janey, what would you do if I turned into a cow?'' he asked his little sister.

She was puzzled. ''What would you do, Ben?'' she asked sweetly.

''Nothin','' he said easily.

''Me, too,'' she said adoringly.

He put his arm around her and they headed out the back door toward the swings.

''Ben, what would you do if my dolly turned into a cupcake?'' She laughed hilariously at her own cleverness.

''Janey,'' Ben said sternly, ''now I'm not going to play with you if you act so silly!''