I cannot believe it. or "That will blow you away." Something is very exciting or surprising. The exploding head can also be used to express shock or awe.
The exploding head emoji was introduced in 2017 and released as part of the Unicode 11.0 standard. This emoji can be found under the smileys and emotions
category. Because the exploding head emoji has been around for quite some time, it should display correctly in the majority of operating systems.