Most versions of elephant’s toothpaste use 30% hydrogen peroxide. The outcome is spectacular. However, 30% hydrogen peroxide is quite corrosive and should be handled with great care. A much safer alternative is to use 6% hydrogen peroxide, as you’ll see in this video. The reaction is not as spectacular but it is still very cool and much safer to conduct.
The demonstrator in this video uses baker’s yeast to catalyze the reaction. This is a safer alternative to potassium iodide or manganese dioxide which are typically used for this reaction.