Don't know if it's already been mentioned
Armadillo goes at such a high speed that it penetrates indestructible plate of metal or any other material. It happens when in 1/100 seconds it covers more than radius distance. Its hard to achieve with default sized dillo but much easier with smaller ones.
i think it can be used in some spectator levels or levels with small dillos
here's the default sized dillo goes through 2 indestructible metal plates
used "uber force"