Looks like a broken tree trunk and is also hollow. This log is almost closed at the top and has a small hole, which can turn the log into a cave for e.g. shrimps or small cichlids. The entrance hole is about 15 mm in diameter. Of course you can also use it to fix a plant there.
This part is in the bargain corner because it is a single piece of a discontinued idea/model series. Without defects.
Height approx. 12 cm
Ø trunk inside ca. 3-3,5 cm
small hole Ø approx. 15 mm