For those wondering what is going on in this gif, here is an explanation. Apologies for any errors. The purpose of this demonstration and reaction is to alter aluminum to show how it is actually a decently reactive element. This reactivity is primarily observed in the appropriately named reactivity series in which a selection of metals are reacted with aqueous solutions, usually acidic ones in order to determine how reactive they are. In the case of aluminum, you have to choose specific solutions to actually show its potential because aluminum will react with the oxygen in the air to produce a layer of aluminum oxide that coats it, effectively blocking displacement reactions that could take place between the metal and an array of solutions. This is shown well in the source video as aluminum is paired with two different acidic solutions. Essentially if you have two acidic solutions with a similar concentration and amount they will behave similarly, however in the case of aluminum certain acidic solutions are unable to get passed that aluminum oxide layer where as others can. However if two similarly concentrated acidic solutions interacted with pure aluminum then the results wouldn't be that different.
The acidic solution that is able to break through that barrier is one containing copper chloride. The chloride ions in this compound are able to react with the aluminum ions in the aluminum oxide layer, effectively breaking it apart. This allows the intended displacement reaction to take place. When that reaction does take place you'll see some bubbles of gas (most likely hydrogen with perhaps a bit of oxygen) being produced with maybe some copper precipitate. When the gas produced by the reaction is ignited it retains a teal/green color from the copper in the acidic solution. Overall compared to other experiments with a metal and an acidic solution this one with aluminium does produce a decent amount of energy in the form of heat and just general output in the form of other precipitate and gasses.
TL;DR - Acidic solution containing copper chloride can break down a protective layer that is on aluminum, allowing it to react with the acid. Igniting the produced gas produces the teal flame due to the copper in the acidic solution.