I want to block packets to a terminal.

I want to prevent packets from reaching a terminal in a LAN (VLAN).
Alternatively, you can prevent packets from reaching anywhere from a particular terminal.
I would prefer a temporary or easy recovery.
For example, is it possible to send fake arp packets over broadcasts and send them to dummy terminals?

Supplemental
You pointed out that it is an XY problem, so I will correct it.
Suppose you have a misconnected NAS or router in a VLAN that you do not know physically where it is.
When other devices are no longer connected to the Internet because of that,
As a first aid to find the cause, I would like to make it possible for other devices to use the Internet during the cause determination process.

I thought it would be better to block the packets to the cause terminal using the ip address and MAC address of the cause terminal.
And I wondered if, for example, it could be achieved by rewriting the ARP table of all other terminals with fake ARP.
Can't you solve this problem by using arp or by using arp?
Thank you for your cooperation.