Summons OOM killer or just abuses the mem.
Download from releases.
Or install with go get github.com/vearutop/oomkome.
Usage: oomkome <memory_size>
memory_size can be a number of bytes, or be in form of xK, xM, xG
oomkome 1G
Eating bytes: 1073741824
Done in 4.876682376s
Filling speed: 209 MB/s
System heap: 1087 MB
Sleeping 10s