1. Switch class to spy.
2. Use invisibility watch to make your way behind sentry.
3. Sap sentry.
4. Shoot Bird, causing bear to fall and die.
5. Get a friendly pyro to hit the bees with his flaregun
6. Hop down, backstab the lion and T-rex
7. Laugh at the gnome, helpless on the other side of the hole.
8. Collect prize.