Bunch of IP's in ARP table from MAC that is not on my LAN

Its a cisco device that is plopping a bunch of ARP connections on my router.
Going to try and block it but curious about what it means.

 0 D 10.0.0.157      4E:38:55:84:72:B4 lan                                         
 1 D 10.0.0.155      00:15:6D:3A:26:B1 lan                                         
 2 D 71.153.40.13    00:00:0C:8D:B2:90 wan                                         
 3 D 65.55.158.118   00:00:0C:8D:B2:90 wan                                         
 4 D 174.17.16.164   00:00:0C:8D:B2:90 wan                                         
 5 D 216.52.233.74   00:00:0C:8D:B2:90 wan                                         
 6 D 20.20.20.238    00:00:0C:8D:B2:90 wan                                         
 7 D 24.234.132.156  00:00:0C:8D:B2:90 wan                                         
 8 D 66.119.9.219    00:00:0C:8D:B2:90 wan                                         
 9 D 70.249.33.18    00:00:0C:8D:B2:90 wan                                         
10 D 68.89.210.81    00:00:0C:8D:B2:90 wan                                         
11 D 20.20.20.21     00:00:0C:8D:B2:90 wan                                         
12 D 98.129.184.21   00:00:0C:8D:B2:90 wan                                         
13 D 68.235.15.34    00:00:0C:8D:B2:90 wan                                         
14 D 216.106.26.204  00:00:0C:8D:B2:90 wan                                         
15 D 216.106.1.2     00:00:0C:8D:B2:90 wan                                         
16 D 10.0.0.152      00:07:E9:BF:EE:F6 lan                                         
17 D 216.106.26.206  00:00:0C:8D:B2:90 wan                                         
18 D 184.51.156.160  00:00:0C:8D:B2:90 wan                                         
19 D 209.85.225.113  00:00:0C:8D:B2:90 wan                                         
20 D 74.125.115.100  00:00:0C:8D:B2:90 wan                                         
21 D 209.85.225.104  00:00:0C:8D:B2:90 wan                                         
22 D 209.85.225.154  00:00:0C:8D:B2:90 wan                                         
23 D 209.85.225.125  00:00:0C:8D:B2:90 wan                                         
24 D 216.52.233.73   00:00:0C:8D:B2:90 wan                                         
25 D 75.126.45.217   00:00:0C:8D:B2:90 wan                                         
26 D 209.85.225.139  00:00:0C:8D:B2:90 wan                                         
27 D 72.21.203.145   00:00:0C:8D:B2:90 wan                                         
28 D 89.149.169.11   00:00:0C:8D:B2:90 wan                                         
29 D 128.242.240.93  00:00:0C:8D:B2:90 wan                                         
30 D 192.168.15.105  00:00:0C:8D:B2:90 wan                                         
31 D 199.16.156.11   00:00:0C:8D:B2:90 wan

I forgot that my modem is bridged to the ISP. That is traffic from their router I believe.